Russia plans to 'annex' Ukraine's Donetsk, Lugansk regions: US official

Russia is planning imminently to "annex" the two eastern regions of Ukraine battered by its invasion after failing to overthrow the Kyiv government, a senior US official said Monday.

"According to the most recent reports, we believe that Russia will try to annex the 'Donetsk People's Republic' and 'Lugansk People's Republic' to Russia," said Michael Carpenter, the US ambassador to the Organization for Security and Co-operation in Europe.

"The reports state that Russia plans to engineer referenda upon joining sometime in mid-May," he told reporters in Washington.

Carpenter said that the United States also believed Russia was considering a similar plan in a third region, Kherson, where Moscow has recently solidified its control and imposed use of its ruble currency.

"We think the reports are highly credible. Unfortunately we have been more right than wrong in exposing what we believe may be coming next, and so that is part of what we're trying to do here."

Russia in 2014 said it had annexed Ukraine's Crimea peninsula but it has stopped short of actions in similar areas with large numbers of Russian speakers, whose cause it has repeatedly cited in its invasion.

"Such sham referenda -- fabricated votes -- will not be considered legitimate, nor will any attempts to annex additional Ukrainian territory," Carpenter said.

"But we have to act with a sense of urgency."