Dozens of Russians linked to Russia's gradual takeover of Crimea could face U.S. and EU travel bans and asset freezes on Monday, after six hours of crisis talks between Washington and Moscow ended with both sides still far apart.
Moscow shipped more troops and armour into Crimea on Friday and repeated its threat to invade other parts of Ukraine in response to violence in Donetsk on Thursday night despite Western demands to pull back.
EU diplomats will choose from a long list of 120-130 possible Russian targets for sanctions on Sunday, as pro-Moscow authorities who have taken power in Crimea hold a vote to join Russia in the worst East-West confrontation since the Cold War.
Several diplomats dismissed a German newspaper report that said the list would include the heads of Russia's two biggest companies, energy giants Gazprom and Rosneft.
U.S. Secretary of State John Kerry said Russia would be guilty of a backdoor annexation of Crimea if its parliament ratified the Crimea referendum, which is taking place after an armed takeover of Crimea and gives voters no chance to say "no".
He has warned Moscow that U.S. and EU sanctions could be imposed as soon as Monday, although U.S. officials said after Kerry's marathon meeting with Russian Foreign Minister Sergei Lavrov in London on Friday the door was still open for more talks.
Lavrov played down his own ministry's threats, saying Moscow had no plans to invade Russian-speaking eastern Ukraine, where pro-Moscow groups have occupied some government buildings.
But he said Russia would respect the referendum result. Preliminary partial results are expected late on Sunday, with final results on Tuesday.
STOCK MARKET FALLS
Russia's stock markets tumbled and the cost of insuring its debt soared on the last day of trading before the Crimea vote. Brent crude oil rose by more than $1 as traders worried the crisis was set to escalate.
Foreign holdings of U.S. Treasuries have also plunged this week, leading some traders to speculate Russia has cut its dollar reserves to support the rouble and avoid any sanctions.
An EU diplomat said he expected the final list of those who could be sanctioned on Monday to be between "tens and scores" of people from the list, which runs to five pages.
Germany's Bild newspaper reported that Alexei Miller, boss of natural gas monopoly Gazprom, and Igor Sechin, head of Russia's biggest oil firm, Rosneft, would be among those targeted, along with senior ministers and Kremlin aides.