Russia said Tuesday that six humanitarian corridors opened last week leading from Aleppo were still operational. Officials added that Russian and Syrian warplanes had not bombed the besieged and war-torn Syrian city for seven days.

Russian Defense Ministry spokesman Major-General Igor Konashenkov said warplanes hadn’t even approached Aleppo, let alone conduct airstrikes since Moscow announced a pause in hostilities last Tuesday.

“Flights over Aleppo by the Russian and Syrian air forces have been completely halted for the last seven days,” he reportedly said, adding that the corridors which were opened for humanitarian relief on Oct. 20 during a 48-hour ceasefire were still operational.

Konashenkov also said that 50 women and children left Aleppo using these humanitarian corridors Monday, escorted by the Russian military.

But Russia’s claims contradict that of rights organizations like the Syrian Observatory for Human Rights, which said airstrikes had resumed in some areas Sunday. The organization said districts on the west of Aleppo were hit Tuesday, and added that air strikes continued outside Aleppo during the ceasefire.

Meanwhile, NATO Secretary-General Jens Stoltenberg said Tuesday a Russian naval battle group was spotted heading to Syria and could be used to target civilians in Aleppo. Stoltenberg urged Moscow to implement a lasting ceasefire.

“The battle group may be used to increase Russia’s ability to take part in combat operations over Syria and to conduct even more air strikes against Aleppo,” he reportedly said at a news conference. “The concern is that the carrier group can be used as a platform for increased air strikes against civilians in Aleppo.”

The battle group has fighter bombers and helicopters on board and is joining at least 10 other Russian vessels already deployed off Syria’s coast, diplomats said.

The United Nations said Monday it is suspending plans to evacuate patients from rebel-held east Aleppo. U.N. Under-Secretary-General for humanitarian affairs and emergency relief coordinator Stephen O'Brien expressed his frustration in the organization’s inability to evacuate any of the patients in the besieged city during the ceasefire and blamed all parties involved in the war that is now in its sixth year.

“I am outraged that the fate of vulnerable civilians — sick and injured people, children and the elderly, all in need of critical and life-saving support — rests mercilessly in the hands of parties who have consistently and unashamedly failed to put them above narrow political and military interests,” O’Brien said in a statement.

“As I have said before, we are facing an unparalleled humanitarian catastrophe in eastern Aleppo. Due to the violence and besiegement, east Aleppo has not been reached with humanitarian assistance since early July of this year,” he said.

He urged all warring parties and member nations to reach a consensus “before it is too late.”