US slams Putin's visit to Crimea as provocative and unnecessary

WASHINGTON (AFP) - The United States Friday denounced a trip by Russian President Vladimir Putin to annexed Crimea as "provocative" and warned it will only exacerbate tensions in Ukraine.

"We do not accept Russia's illegal annexation of Crimea. Such a visit will only serve to fuel tensions," National Security Council spokesman Laura Magnuson said.

Putin made a surprise visit to the Crimean port of Sebastopol to inspect Russian naval forces as part of celebrations to mark the World War II Soviet victory over the Nazis.

But State Department spokesman Jen Psaki described the visit as "provocative and unnecessary."

"Crimea belongs to Ukraine," she added, referring to Ukraine's southern peninsula which was annexed by Moscow after a referendum organised by pro-Russian separatists in March.

The crisis has since shifted to eastern Ukraine where Kiev has struggled to put down a similar uprising by pro-Russian militants.

Tensions in Ukraine are likely to be raised on the sidelines of a visit by Secretary of State John Kerry to London next week when he is due to meet counterparts for talks on Syria.

Kerry spoke with his Russian counterpart Sergei Lavrov by phone Friday about how to de-escalate tensions on the ground.

"What we're waiting for is actions," Psaki said, after Russia called on separatists to halt a fresh referendum being organised in eastern Ukraine cities on Sunday.

"If this crisis is going to end, we need their words to be made real," Psaki said.

"So if they are serious about what they are saying, they need to tell separatists to lay down their arms to release those who are being held."

She also condemned violence in the southeastern Ukrainian city of Mariupol in which 21 people were killed in fighting between Ukrainian troops and pro-Russian rebels.

"We condemn the outbreak of violence caused by pro-Russia separatists this morning in Mariupol, which has resulted in multiple deaths," Psaki told reporters.

"We continue to call for groups who have jeopardized public order by taking up arms and seizing public buildings in violation of Ukrainian law to disarm and leave the buildings they have seized."