The United States warned it would not accept any use of Russian troops in Ukraine as it confirmed that Moscow had redeployed "significant" military forces near the border, AFP reports.
The United States warned it would not accept any use of Russian troops in Ukraine as it confirmed that Moscow had redeployed "significant" military forces near the border, AFP reports.
"We are monitoring the situation carefully. We will not accept the use, under any pretext, of any Russian military forces in eastern Ukraine," said Josh Earnest, a White House spokesman.
"Reports from Moscow that the Russian defense ministry is considering creating military cordons in eastern Ukraine are also troubling."
A Russian defense ministry source told RBK news agency this week that troops were prepared to enter Ukraine's insurgent regions in order to "put up barriers between the civilian population and the Ukrainian army."
Ukrainian officials have separately told EU and G7 teams in Kiev that they have evidence of 10 additional tanks and sealed trucks coming over the border close to Lugansk in the past 24 hours.
"We have our own information that Russia has redeployed military forces to its border with Ukraine," State Department spokeswoman Jen Psaki told reporters.
"This is the closest Russian troops have come to the Ukrainian territory since their invasion of Crimea."
Moscow has annexed the southern Ukrainian peninsula, after invading the territory earlier this year.
Ukraine's Western-backed President Petro Poroshenko meanwhile declared a weeklong unilateral ceasefire to give pro-Russian rebels a chance to disarm and released a sweeping peace plan for curbing the uprising.
The 14-point initiative came after two calls made by Poroshenko to Russian strongman Vladimir Putin to try to garner his support.
The US Treasury Department blacklisted seven Ukraine separatists, saying their activities threaten the peace and sovereignty of the country.
Topping the list was Vyacheslav Ponomaryov, the rebel leader in the eastern separatist stronghold of Slavyansk whose group kidnapped observers from the European security body OSCE in May and continues to hold them.
The US is "confident" that Moscow sent tanks and rocket launchers last week from the deployment site in southwest Russia into eastern Ukraine where pro-Russian separatists are fighting to break away Kiev, Psaki said.
Washington has information that "additional tanks have been prepared for departure" at the same site, she added, saying artillery had also been gathered at a deployment site.
Russia 'masking' support
But separatists said they would not lay down their arms, until Kiev had pulled back its forces.
Most of the equipment being gathered in southwest Russia is no longer used by Russian forces "and we believe that Russia may soon provide this equipment to separatist fighters," Psaki said.
The equipment is of a type still used by Ukrainian forces, "leaving the impression that the desire here is to mask the Russian hand and allow the separatists to assert... that this is materiel that they've captured on the battlefield from Ukrainians," a US administration official said earlier.
On Thursday, NATO reported another unannounced buildup of Russian forces near Ukraine that Alliance chief Anders Fogh Rasmussen called "a very regrettable step backwards."
Rasmussen said the Russian military had deployed "at least a few thousand more" troops in what appeared to be a reversal of the pullback Moscow had begun at the start of the month.