Russian warned against US sanctions over Ukraine crisis, saying Washington’s threats regarding this issue is unacceptable.

Russian warned against US sanctions over Ukraine crisis, saying Washington’s threats regarding this issue is unacceptable.

A threat by US President Barack Obama that more sanctions would befall Moscow if the agreement, reached Thursday with Ukraine and the EU, failed was "absolutely unacceptable," Kremlin spokesman Dmitry Peskov told Russian television.

"Our Western colleagues are trying to push responsibility towards our side. But it must be underlined: it is a collective responsibility," he said.

He pointedly declared that "there are troops close to the Ukrainian border". "Some are based there, others have been sent as reinforcements due to the situation in Ukraine," he added.

The comments appeared to be a warning shot to Washington that the situation could quickly degrade if Moscow were punished for a failed implementation of the accord.

The White House said it was watching Moscow to see if it is holding up its end of the deal.

"We expect and we will be watching whether Russia does or does not uphold its responsibility to use its very considerable influence to restrain and withdraw those irregular militia from the buildings and spaces that they've occupied," said National Security Advisory Susan Rice.

In a phone call on Friday with Russian Foreign Minister Sergei Lavrov, US Secretary of State John Kerry said the following days would be "pivotal", a senior State Department official said.

The top US diplomat stressed that "all illegal armed groups must be disarmed and all illegally seized buildings must be returned to legitimate owners," according to the official.