Nine coronavirus patients died in a Russian hospital in the southern city of Vladikavkaz after an oxygen pipe burst underground, cutting supply to an intensive care ward, Russian news agencies reported on Monday.

"Nine patients with coronavirus died due to a lack of oxygen," the TASS news agency cited the local health ministry as saying.

"A total of 71 people were in intensive care, not all were (receiving) oxygen supply," TASS quoted the ministry as saying.

Regional authorities have agreed with the defence ministry to supply oxygen to all of the city's hospitals from the town of Mozdok, around 80 kms (50 miles) north of Vladikavkaz, RIA reported.

"There was a burst in the oxygen pipe from the reservoir, which is underground, and the oxygen supply was stopped," acting head of the North Ossetia region, where Vladikavkaz is located, was cited by RIA news agency as saying.

"Medical staff has started to connect the patients who are on ventilators to oxygen tanks. Oxygen tanks have started to arrive," acting head of North Ossetia Sergei Menyailo said.