Crimea declared independence from Ukraine and applied to join Russia as Ukraine began drawing up plans to mobilise 40,000 reservists to counter Russia's "blatant aggression" in the troubled region.
A top Chinese diplomat repeated Beijing's call for calm and restraint in Ukraine, but avoided commenting on the referendum in Crimea after the region's Moscow-backed leaders declared a 96 per cent vote in favour of joining Russia.
Chinese Vice Foreign Minister Li Baodong, speaking to reporters ahead of a visit to Europe by President Xi Jinping later this month, said that a political settlement was the only way to resolve the Ukraine crisis.
"We hope all parties can calmly maintain restraint to prevent the situation from further escalating and worsening. Political resolution and dialogue is the only way out," Li said.
Watch: Pro-Russian Crimeans celebrate in Simferopol after vote
Official results from Sunday's referendum showed 96.77 per cent of the voters in the mostly Russian-speaking region opting for Kremlin rule in what would be the most radical redrawing of the map of Europe since Kosovo's 2008 declaration of independence from Serbia.
Crimea's lawmakers also declared the Russian ruble the peninsula's second official currency and vowed to "disband" the Ukrainian military units stationed across the region - a move that threatens to inflame the raging security crisis on the European Union's eastern frontier.
Ukraine's interim president, Oleksandr Turchynov, denounced the vote as a "great farce" and watched from a podium as agitated lawmakers approved a partial mobilisation of the army aimed at countering Russian troops' effective seizure of Crimea.
The ex-Soviet nation's acting defence minister, Igor Tenyukh, also firmly told reporters that the "troops deployed [in Crimea] will stay there".
Russian President Vladimir Putin has signalled no intention to turn back on what he describes as his defence of ethnic Russians who, according to Moscow, have come under increasing attack from Ukrainian ultra-nationalists since last month's ouster in Kiev of a pro-Kremlin regime by a far more nationalist but Western-leaning team.
Putin today will make a special address on the crisis that will be attended by lawmakers from Russia's two houses of parliament.
Crimea's self-declared leader, Sergiy Aksyonov, also tweeted that he was flying to Moscow for talks.
The Soviet Union's last leader, Mikhail Gorbachev, said the world should welcome the prospect of Crimea becoming part of Russia as it rectifies a historic mistake.
Gorbachev said that Crimea had only ended up in the territory of post-Soviet Ukraine because it had been transferred from Russia by Soviet leader Nikita Khrushchev when both countries were part of the USSR.
But the overwhelming margin of victory for the pro-Kremlin camp underscores the mistrust the heavily Russified southeast of Ukraine shares for the European leanings of those who rose to power on the back of three months of protests in Kiev.
Alcohol-fuelled celebrations swept cities across the diamond-shaped Black Sea peninsula as Russian flags flew and refrains from Soviet-era songs filled the rain-soaked streets.
"We're free of the occupation!" Lucia Prokorovna, 60, said amid bursts of fireworks in Russia's historic naval port of Sevastopol late on Sunday.
"Ukraine was attached to Crimea like a sack of potatoes," he said.
Additional reporting by Reuters