Lavrov Russia Ukraine War Putin Obama
U.S. Secretary of State John Kerry (R) and Russia's Foreign Minister Sergei Lavrov pose for a photograph before their meeting at Winfield House, the home of the U.S. ambassador in LondonReuters

Russian Foreign Minister Sergei Lavrov has declared that Russia will not order its forces into eastern Ukraine, despite US intelligence reports that 50,000 Russian troops have been mobilised along their shared border.

"We have absolutely no intention and no interests in crossing the Ukrainian border," Russia's chief diplomat told Russian state television.

"We (Russia and the West) are getting closer in our positions," he added.

Lavrov said that recent discussions with other leaders showed the promise of a "possible joint initiative which could be presented to our Ukrainian colleagues".

US officials are reacting with alarm to Russia's buildup of military forces along the Russia-Ukraine border, Russian President Vladimir Putin's rhetoric and his claims that ethnic Russians face "brutality" in Ukraine.

"The thinking in the US government is that the likelihood of a major Russian incursion into Ukraine has increased," a senior US official said.

US defence officials believe that the number of troops stationed on the Ukraine border is far higher than a training exercise demands. US observers are concerned that none of the Russian troops has returned to base.

Russian troops have seized three military bases in Crimea following President Vladimir Putin's annexation of the Russian-dominated region.

There are now concerns that Putin has set his sights on another area with a prominent Russian-speaking population, Transnistria.

Gen. Philip Breedlove, Nato's supreme allied commander for Europe, has expressed deep concern about Russia's military manoeuvres.

"We're all concerned about what Russia is doing on the border of Ukraine," Breedlove said after the first briefing. "The size of the forces have a message that are not congruous with respecting the borders."