There are fears that contaminated drinking water could spread disease in the besieged Ukrainian city of Mariupol.

Mariupol City Council has warned that improper burials in parks, gardens and public areas is leading to pollution of the city's limited water sources and supplies.

The warning comes as the Ukrainian war enters its fourth month and as the city’s Deputy Mayor, Sergei Orlov, accused Russian of keeping civilians in Mariupol as hostages.

Speaking to RTÉ's Morning Ireland, Mr Orlov accused Russia of targeting Ukrainians in areas occupied by its troops.

"Russia does everything to destroy Ukraine. They kill Ukrainians. They deport Ukrainians. They rape our women. In occupied territory it is dangerous of [to] be Ukrainian. You can lose your life," Mr Orlov said.

A person is seen walking among freshly dug graves at Mariupol' Starokrymsky cemetery

Over the past three months bodies have been buried throughout the city in parks, gardens and public areas. Officials have also reported mass graves were also used.

Mr Orlov said: "Before the war the population of Mariupol was about half-a-million citizens. At the moment we estimate that about 150,000 citizens are still left in Mariupol.

"It is my native city. For me to see the level of destroyment [destruction], to see the number of killed people, to see actions from occupation army is difficult."

He said life remains difficult for the 150,000 people remaining in the city.

"The city is in total humanitarian crisis. The city lives without any utilities - without electricity, without water, without sanitary systems, without natural gas, and with a lack of work, a lack of money, a lack of food, a lack of social and medical help. That is the current situation in Mariupol.

He said the citizens are "like hostages of the Russian occupation army".

He said Mariupol City Council is concerned about the spreading of disease through contaminated water.

He said the council is "very scared and concerned about possible infection" because people who died in the city were not buried "in a safe way".

"We are very concerned and are telling this to the World Health Organization to pay attention to this," added the Deputy Mayor.

"We are also very concerned that people are hungry. People do not have economic activity. They do not have jobs. They do not have money.

"We are also very concerned about continuing deportation of our citizens to Russia," he added.

A Russian serviceman patrols the destroyed part of the Ilyich Iron and Steel Works

Reflecting on three months of war, Mr Orlov said it had changed life in Ukraine.

"We should not forget that here in Ukraine we fight for freedom and independence. We still want only one thing - to stay alive, to be Ukrainian and not to be afraid to be Ukrainian in Ukraine because Russia does everything to destroy Ukraine as a nation.

"Russia does everything to destroy Ukraine. They kill Ukrainians. They deport Ukrainians. They rape our women. In occupied territory it is dangerous of [to]be Ukrainian. You can lose your life. You may be killed if you are Ukrainian. They do everything to destroy us and we fight for freedom," said Mr Orlov.

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He said there is strong international support from the UK, US, and parts of the EU.

"We see strong support by some European countries - the Baltic region, Poland. We don’t see strong support by big European countries. They may be wasting time, but this time we pay with lives of our soldiers.

He clarified Germany and France were the bigger European countries that he referred to.

"It would be great for Ukraine if their support was much [more] and faster," said Mr Orlov.

"Even it is the situation in Mariupol that we have a lot of motivated soldiers but they still do not have enough hard weapons.

He said the city council believes that only a military victory can lead to negotiations and the end of war.

"That’s why we should win on the fields of war with Russia and push them to negotiate," Mr Orlov said.

Yesterday, Russian State Media reported that the head of the separatist Donetsk region said Ukrainian fighters who surrendered at the Azovstal steel plant in Mariupol will be put on trial.

Mr Orlov said he could not comment on this as it is part of negotiation between Ukraine and Russia.