Russian Foreign Minister Sergei Lavrov on Thursday said there was so far no agreement between Moscow and Washington on the situation in Ukraine, after talks in Rome with US Secretary of State John Kerry.

"For the moment we cannot report to the international community that we are in agreement," Lavrov was quoted by Russian news agencies as saying, adding that he would inform President Vladimir Putin about the talks on his return.

"We agreed that we will study further those thoughts that John Kerry gave me today about concrete prospective steps," Lavrov said, according to Interfax news agency.

"We want to clarify more deeply what our partners mean when they suggest some kind of international mechanism, what its content would be," he added.

Lavrov strongly criticised US visa restrictions imposed on Thursday against Russians and Ukrainians it blames for the current crisis, saying they were "a threat".

He warned of a "constant building of pressure in the atmosphere", but said Kerry had told him the visa restrictions had not yet been implemented.

The top Russian diplomat also criticised NATO's announcement on Wednesday that it was reviewing its cooperation with Russia including the suspension of a joint mission to destroy Syrian chemical weapons.

"We need these structures no more than our partners do," Lavrov said.

He added that the international community "has a very strong interest in normal dialogue going on between the West and Russia, without attempts at ultimatums, without attempts to demand that we unilaterally change our position, which in the case of Ukraine our president put in detail and extremely clearly."

Russia's position "has wide understanding in the world," he added.

Lavrov had said in a briefing late Wednesday that he and Kerry had agreed on the need to return to the February 21 deal agreed by Ukrainian protesters and then-president Viktor Yanukovych before his ouster.

But US officials denied that this had been agreed, insisting that such a deal could be reached only with the involvement of the pro-Western Ukraine government that has replaced Yanukovych's pro-Kremlin administration.