UNICEF has warned that millions of families across Yemen could soon be without food, clean water and sanitation because of "the deepening economic crisis and unrelenting violence in the port city of Hudaydah".
"The cost of food, fuel and water supplies has skyrocketed as the value of the national currency has plummeted," said the UN agency in a statement this week.
"Water and sewage treatment services are at risk of collapse because of soaring fuel prices - meaning many of these same children and families may also be without access to safe water and sanitation."
UNICEF said this could lead to disease outbreaks and increased malnutrition, raising the risk of famine.
The humanitarian agency is appealing for talks to establish peace in the war-torn region.
Where is it?
Yemen is at the southern end of the Arabian peninsula and borders Saudi Arabia and Oman. It has been in existence as a state in its current form since the early 1990s.
Yemen is only 30km from Djibouti in Africa, which sits across the Bab al Mandab straits, which means Gate of Tears.
What is Yemen’s history (in brief)?
The Yemeni capital Sana'a is one of the oldest inhabited cities in the world. The 'old city' is a Unesco Heritage site.
In the 19th century, the area that is now Yemen was divided between the British Empire, which occupied the port of Aden and the south, and the Ottoman Empire, which occupied Sana'a and the north.
When the Ottoman Empire collapsed, a Shia Imam from the Zaidi sect consolidated power in the north. Britain continued to occupy the south.
In the 1960s war broke out in the northern part, which saw factions backed by Saudi Arabia and Egypt respectively face off in a civil war. They were in turn backed by the US and the Soviet Union respectively.
The Yemen Arab Republic emerged from this war. Ali Abdullah Saleh became its leader in 1978.
Britain withdrew from Southern Yemen in 1967, which then became a Marxist State called the People's Democratic Republic of Yemen.
Fighting broke out between the northern and southern republics during the 1970s, but co-operation over energy exploration and the collapse of the South’s backer, the USSR, saw the republics unify in 1991 after a popular vote.
Northern leader Ali Abdullah Saleh became head of the new state. A civil war broke out shortly after unification which lasted until 1994.
Mr Saleh remained in power until 2011, when he was replaced by Abdrabbuh Mansour Hadi after a popular uprising during the Arab Spring.
How did the current war break out?
President Hadi faced instability on several fronts when he came to power. Al-Qaeda in the Arabian Peninsula carried out several large attacks on government targets.
Ousted former President Saleh (above), who also retained the loyalty of some military commanders, forged an alliance with his former enemies, the Shia Houthis in the north of the country.
The instability led many Yemenis to become dissatisfied under President Hadi. A Houthi mounted an offensive and took the capital Sana'a in late 2014. President Hadi fled abroad in early 2015.
Saudi Arabia then intervened, along with a coalition made up of United Arab Emirates (UAE), Bahrain, Kuwait, Qatar (until 2017), Egypt, Jordan, Morocco, Senegal and Sudan. The US and the UK are the main international backers of the Saudi coalition.
Is the war a Saudi-Iranian proxy war?
The war is predominantly a local civil war, in which Saudi Arabia has intervened to protect its southern border and to try to prevent a Houthi takeover by restoring to power President Hadi. Saudi Arabia maintains the Houthis are an Iranian proxy.
The Houthis do receive Iranian support but are not Iranian proxies. While the Houthis are Shias, they belong to a different sect to the one that is prevalent in Iran.
Iran is also primarily engaged in Syria, Iraq and Lebanon and does not see Yemen as a vital interest, nor does it want to commit large-scale resources to the conflict.
Iran-Houthi links could be summarised as 'Saudi's difficulty is Iran's opportunity' and even limited support to the rebels achieves this outcome.
Iranian help to the Houthis has escalated since the Saudi intervention. In an effort to choke off this support, a blockade has been imposed on Yemeni ports by the Saudi-led coalition, which has had devastating humanitarian consequences.
Audrey Crawford, Yemen Country Director, Danish Refugee Council
Who else is involved?
The US and the UK are Saudi Arabia’s most powerful supporters. The US signed a $110bn arms deal with Saudi Arabia last year, while the UK has sold around £4.5bn worth of weaponry to Saudi Arabia since 2015.
UK and US personnel have also provided advice in Saudi Arabia’s aerial command and control centre, which both countries say is aimed at avoiding civilian casualties.
What has the human cost of the war been?
An estimated 22.2 million people are in need of humanitarian assistance according to the UN, 13 million people are at risk of starvation.
There have been over 16,000 civilian casualties since March 2015. This includes around nearly 7,000 killed, of whom nearly one in five were children.
Around two million people have been displaced.
RTÉ News spoke to Yemen expert Iona Craig, who has reported regularly from the country.
What’s driving the conflict?
"There are now multiple groups on the ground fighting for several different reasons. They have different end goals and it’s an extremely complex conflict now.
"It started as a civil war - really a fight between two presidents: The former president of Yemen Ali Abdullah Saleh was forced out of power in the Arab Spring uprising of 2011.
"The man who replaced him [was] President [Abdrabbuh Mansour] Hadi. Saleh used the Houthis to seize the capital in September 2014, but it’s morphed into a broader regional conflict now between Saudi Arabia and Iran as well as a multi-faceted conflict on the ground with all of these groups fighting for different reasons."
What’s the role of Saudi Arabia in Yemen’s conflict?
"Saudi Arabia intervened in Yemen’s civil war back in March 2015. That was at the behest of the Saudi Minister of Defence at the time, Mohamed bin Salman (below) - he is still Minister of Defence and he later became Crown Prince and a somewhat infamous character.
"Saudi Arabia formed a coalition quite rapidly of regional nations from the Gulf Co-operation Council as well as other countries such as Senegal and Sudan and the other key player with them has been the United Arab Emirates.
"Saudi’s part in the war has really been leading this bombing campaign which has resulted in nearly 19,000 air raids in Yemen since the war began.
"The UN has said that has caused 60% of the civilian casualties in the conflict and has had many other effects. There have been import restrictions on the country, for example, which has affected food supplies.
"And the reason Saudi got involved in the first place was, they said, to get President Hadi, the legitimate government, who’d been forced out by the Houthis, back into power in Yemen.
"They view the Houthis not just as an ally of Iran, but a proxy of Iran. That was really an overblown and very much an exaggerated relationship before the war in Yemen, but has become something self-fulfilling and there’s now a fairly strong relationship between the Houthis and Iran."
Have food supplies been curtailed and is this deliberate?
"Yemen was the poorest country in the Middle East before the war started and there has long been a problem with malnutrition amongst children in Yemen.
"But because of the restrictions put in place on imports into the country - restrictions put in place by the Saudi-led coalition; because of the collapse of the currency; because of government wages going unpaid for more than two years, all of those have contributed to the food crisis in Yemen.
"Now some of that is deliberate. There is evidence that there has been deliberate targeting in the air campaign of agriculture, of fishermen and even warehouses with the aim of an economic siege, particularly in Houthi-controlled territory.
"I think most people view that as a tactic by the Saudi coalition to create unrest in those territories held by the Houthis to cause civil unrest so that people will rise up against the Houthis to try and overthrow them internally.
"But of course the impact has really been particularly on children, the very young, the very old, the most vulnerable, this problem of mass starvation. This has been happening in Saudi-controlled areas as well as the Houthi-controlled North.
"So there is evidence that this is absolutely deliberate, but at the same time the Saudis would argue that they are pumping in millions of dollars into the central bank and that they are providing aid and funding to the country as well.
"But of course one doesn’t outweigh the other. The damage that is being done as a result of the import restrictions, as a result of the currency collapse, as a result of the air war, as a result of wages going unpaid for so long - that damage far outweighs any aid that is been given to the country whether it’s by Saudi Arabia, the UK, or even the US."
Iona Craig, Investigative Journalist and expert on Yemen
What is the role of global powers in Yemen?
"Obviously the US and the UK as well as other European countries have been selling a considerable amount of arms to Saudi Arabia and to the UAE over the course of the conflict and for many years before.
"But the US is more heavily involved, essentially because they provide mid-air refuelling for fighter jets carrying out these bombing raids on a daily basis.
"Without that mid-air refuelling, planes wouldn't be able to do their bombing runs. If they stop that mid-air refuelling, bombing runs literally have to stop tomorrow.
"I’m sure they’d probably find an alternative in the long-run, but the US is crucial to the air war continuing. They’ve also been helping more heavily on target selection - or their argument is they're not helping in target selection, they've created a list of non-targets, i.e. targets, sites which should not be hit.
"I think the excuse of both the US and UK over the course of this war has been that they have tried to mitigate civilian casualties by helping the Saudis with international humanitarian rules and both in their training and in their processes they use for target selection. Unfortunately that hasn’t played out.
"The US has given millions of dollars to the Saudis for training on international humanitarian rules, yet there have continued to be cases of mass civilian casualties, there has been mounting evidence of blatant disregard for civilian life and even the deliberate targeting of civilians.
"Probably the most famous case has been the airstrike on a school bus which killed dozens of children in northern Yemen and air raids on civilians have gone up every year since the air war began.
"Despite the fact the US and the UK and other countries said Saudi is taking steps to avoid civilian harm and improve their targeting, that’s just not happening.
"The reality on the ground is you're still getting these events where civilian targets are being hit and there are mass civilian casualties."
Is there any kind of effective peace process?
"There is a special UN envoy, there was a new one appointed in March of this year, Martin Griffiths, who has been attempting to bring the parties to the conflict together for discussions.
"In fact last month there was a meeting in Geneva but unfortunately the Houthis didn't even make is as far as Geneva, so it never happened.
"So at the moment we are a long way from reaching even talks, never mind reaching a political solution.
"There are attempts now at confidence-building measures, which include prisoner swaps, to re-open airports in Sana'a and Houthi-controlled territories but there are no indications that the parties to the conflict are going to sit down and talk to each other and in fact the conflict has escalated on the ground and the political process that is in place doesn’t involve any agreement with the fighters on the ground and is not representative.
"And this is part of the issue: Even if the Saudi coalition pulled out tomorrow, this would not mean an end to the war in Yemen because the country is so fragmented, so there is very little, if any light at the end of a very long dark tunnel for the civilian population in Yemen at the moment."