Northern Ireland has recorded a further eight Covid-19 related deaths during the past 24 hours, taking the official Department of Health toll to 688.

An additional 822 cases have been recorded from tests on 3,283 individuals.

There are 361 confirmed Covid-19 patients in hospital, with 44 in ICU, 39 of whom are on ventilators.

The seven-day infection rate per 100,000 for Northern Ireland is 316.

The worst area is Mid Ulster, with a rate of 495.5 followed by Derry and Strabane on 428.1 and Belfast on 423.8.

Earlier, concerns were expressed at a Derry hospital over low oxygen supplies.

Altnagelvin Hospital has been treating large numbers of patients with Covid-19 who require high levels of oxygen.

The Western Health Trust is using 800-900 litres of oxygen per minute, around three times the normal level of usage.

Sean Gibson, head of estate management at the trust, said they have never seen this level of oxygen usage.

"I am concerned that there isn't enough oxygen to treat patients, it's the biggest concern," he told the BBC.

"If we're experiencing the growth in numbers that we have then we may not have enough oxygen to treat them. We may have to ration oxygen, it's that serious."

The hospital in uses a green, amber and red alert system to monitor the oxygen levels.

While the levels are between green and amber, last week they were edging towards red.

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Mr Gibson added: "If things continue as they are then we will be in the red very, very quickly, which is a very, very serious situation.

"This plant has never seen this type of oxygen usage.

"It's designed to deliver but we don't really know until we see it happening.

"I don't think we're going to run out of oxygen, what's going to happen is we won't have enough oxygen for all the patients that come through the hospital and doctors will have to think about who will get oxygen, what levels of oxygen they will be able to give them."

However, chief nursing officer Charlotte McArdle said oxygen levels across hospitals in Northern Ireland are monitored on a daily basis with mitigation measures planned if required.

"That is one of the reasons why the Belfast City Hospital remains the Nightingale Hospital, because there is increased infrastructure and a lot of work done to ensure that it would have significant oxygen supplies to maintain a very high level of ICU," she said.

"This is critical, oxygen is part of our medicine therapy, it is looked at on a daily basis."

Meanwhile, the youngest person to die in Northern Ireland after testing positive for Covid-19 has been named locally as Aaron Doherty from Derry.

The 17-year-old, who is understood to have had underlying health conditions, battled the virus in recent weeks. He died on Tuesday.

Northern Ireland's Deputy First Minister Michelle O'Neill said she cannot imagine the pain felt by Aaron's parents.

"Aaron's passing is a cruel reminder of the situation we are faced with," she added.

'Green shoots of hope' - Foster

Speaking at a media briefing today, First Minister Arlene Foster said there are "green shoots of hope" across Northern Ireland in its fight against Covid-19.

The R rate for case numbers has dropped below one, Mrs Foster said.

"We still have more work to do. We are seeing the number of those died have increased by 47," she said.

"There is evidence of the impact of the restrictions being observed. Activity has decreased significantly across a range of areas. Transport usage is down by 49%, work places by 41% and park visitors by 26%. Supermarkets and pharmacy activity is also down." 

Deputy First Minister Michelle O'Neill said Northern Ireland was almost at the midway point of its four-week circuit breaker. 

Ms O'Neill said that evidence shows that the number of Covid-19 cases are levelling off.

"We want to thank every one of you for your efforts but this is not the time to drop our guards," Ms O'Neill added. 

Children aged 11 will now be required to wear face masks while travelling on transport to and from school, it has been confirmed.

The decision comes as Mrs Foster and Ms O'Neill continued to raise concerns about people congregating at school gates.

Mrs Foster said the issue needed to be addressed as some people are not social distancing nor wearing face masks while waiting outside school buildings.

She said that schools will reopen as planned on Monday.

Additional reporting: PA