NATO, Moscow exchange barbs as UN warns of return to warfare in Ukraine

Russia has dismissed as “hot air” fresh claims by NATO's top commander that Moscow has been sending troops and tanks into eastern Ukraine.

U.S. Gen. Philip Breedlove said on Wednesday that in the last two days equipment had been seen crossing the border, “primarily Russian tanks, Russian artillery, Russian air defense systems and Russian combat troops.”

The remarks drew an immediate response from Moscow. Stating that there was “no evidence” to back up the accusation, senior Russian defense official General-Major Igor Konashenkov added: "We have already stopped paying attention to unsubstantiated statements by NATO's Supreme Allied Commander Europe, General Philip Breedlove, on Russian military convoys he 'observed' allegedly invading Ukraine."

The latest exchange of barbs come as the United Nations Security Council prepared to hold an emergency session on Ukraine amid worries over a renewal of full-scale conflict in the rebel-held east. During that session, a senior UN official warned that open warfare may erupt once more in Ukraine's breakaway

"We are deeply concerned by the possibility of a return to full-scale fighting," Assistant Secretary-General Jens Anders Toyberg-Frandzen told the emergency meeting.

Earlier, Breedlove, speaking in Sofia, Bulgaria, wouldn't say how many fresh troops and weapons have moved into Ukraine and wouldn't specify how the alliance obtained the information.

The West and Ukraine have continuously accused Moscow of fueling a pro-Russian insurgency in eastern Ukraine with troops and weapons — claims that Russia has consistently rejected.

The main city in Ukraine’s east, Donetsk, has seen its heaviest shelling in recent weeks despite a cease-fire signed two months ago between Ukraine and Russia-backed separatists.

The Sept. 5 truce has been violated numerous times. As a result of the latest escalation, Kiev has said it will redeploy forces to prepare for a possible new rebel offensive.

Toyberg-Frandzen warned the Security Council that sporadic low-level battles could "simmer in this way for months."

The Security Council has met well over a dozen times on Ukraine since the crisis began early this year, but little action can be taken as permanent member Russia has veto power.

Al Jazeera and wire services