Russia has told the US that Western sanctions over the Crimea dispute are unacceptable, and has threatened "consequences".

 

俄罗斯向美国透露，西方国家因克里米亚争端而实行制裁是不可接受的，并威胁会有“后果”发生。

 

Russian Foreign Minister Sergei Lavrov issued the warning in a telephone call to US Secretary of State John Kerry.

 

It came hours after Russian and Crimean leaders signed a treaty absorbing the peninsula into the Russian Federation following a disputed referendum.

 

On Wednesday there were reports of an incident at a naval base in Sevastopol.

 

An Associated Press reporter at the scene said pro-Russian self-defence forces had broken into the building - the headquarters of the Ukrainian navy - and raised the Russian flag.

 

But the Ukrainian navy told the BBC a group of civilians who said the base was now on Russian territory had gone into the building to persuade the Ukrainian troops to leave.

 

'Democratic choice'

 

A spokesman for Russian President Vladimir Putin told the BBC the treaty signed on Tuesday was already in effect, and Crimea was now part of Russia.

 

The BBC's Richard Galpin in Moscow says that although it must be approved by Russia's constitutional court and ratified by parliament, there is no doubt MPs will give their full backing when they vote on Friday.

 

On Monday, the US and the EU imposed sanctions on several officials from Russia and Ukraine accused of involvement in Moscow's actions in the Black Sea peninsula.

 

After the signing of the treaty on Tuesday, the White House said those sanctions would be expanded.

 

US Vice-President Joe Biden accused Russia of a "land grab".

 

After Mr Lavrov spoke to Mr Kerry, the Russian foreign ministry said in a statement: "(Crimea) republic residents made their democratic choice in line with the international law and the UN charter, which Russia accepts and respects.

 

"The sanctions introduced by the United States and the European Union are unacceptable and will not remain without consequences."

 

It did not spell out what those consequences might be.

 

Mr Kerry later warned that any incursion（入侵） by Russia into eastern Ukraine would be "as egregious as any step I can think of".

 

"I hope we don't get there," he added.