Residents of Crimea are voting in a referendum decried as illegitimate by the interim government in Ukraine and many western countries. Russia, however, vetoed a UN Security Council resolution condemning the vote.
Some 1.8 million Crimean voters face two options in Sunday's referendum: either becoming a part of the Russian Federation, or returning to Crimea's status under Ukraine's 1992 constitution. The ballots do not offer maintaining the status quo as an option. A return to the 1992 constitution would grant much greater authority to the already semi-autonomous peninsula.
Voters in the majority ethnic-Russian region are expected to approve rejoining Moscow, 60 years after becoming a part of then-Soviet Ukraine in 1954. Polling stations opened at 8 a.m. local time (0600 UTC) around Crimea and will close again 12 hours later on Sunday.
The international community has broadly rejected the referendum's validity: Russia was forced to stand alone on Saturday at a UN Security Council vote on a resolution that would have declared the vote invalid. Thirteen of the 15 Security Council members approved the US-drafted motion, China abstained, and Russia vetoed it.
"Russia - isolated, alone and wrong - blocked the resolution's passage," US ambassador to the UN Samantha Power told the council after the vote.
Steinmeier in last-ditch Moscow appeal
The US and EU have threatened economic sanctions for Russia if the Crimea split goes ahead, albeit without naming specifics and simultaneously pledging continued diplomatic efforts.
"We did not seek out this confrontation. But if Russia does not change its course at the last minute, then on Monday we - the EU foreign ministers - will offer our first appropriate answer," German Foreign Minister Frank-Walter Steinmeier told the Welt am Sonntag newspaper.
"We are in a highly dangerous situation," Steinmeier said. "The tension is also mounting in the east of Ukraine. So far, Russia has turned down every exit option, every step towards de-escalation, and apparently wants to establish facts on the ground which are unacceptable to us."
Ukraine claims Russian incursion
Ukraine's foreign ministry on Saturday said that a contingent of Russian troops had seized a village on the Arabat Spit, a narrow strip of land just east of the Crimean peninsula. Russia's foreign ministry on Saturday said that it was considering "multiple requests" from citizens in the industrial east of Ukraine asking for protection. In largely fruitless talks between Russian Foreign Minister Sergei Lavrov and his opposite number John Kerry on Friday, Lavrov said Russia was not planning an invasion of Ukraine.
Russia denies that troops without insignias controlling much of the Crimea are its soldiers, describing them instead as Crimea's "self-defense forces." Russia's parliament has authorized military missions in Ukraine to protect ethnic Russian citizens, in a vote shortly after the fall of Ukraine's President Viktor Yanukovych on February 22.
Yanukovych triggered major street protests, most notably in the capital Kyiv, late last year when he ditched a planned trade deal with the EU in favor of closer ties to Moscow. This unrest ultimately led to his removal from office, Moscow has not recognized the interim government installed in Yanukovych's place in Kyiv.
msh,slk/crh (AP, dpa, Reuters)