Ukraine crisis: Putin signs Russia-Crimea treaty
President Vladimir Putin and the leaders of Crimea have signed a bill to absorb the peninsula into Russia.
Mr Putin told parliament that Crimea, which was taken over by pro-Russian forces in February, had "always been part of Russia".
Kiev said it would never accept the treaty and the US has called a G7-EU crisis meeting next week in The Hague.
After the signing, Kiev said a Ukrainian serviceman had been killed in an attack on a base in Crimea.
The defence ministry said the attack took place in the capital, Simferopol.
US Vice-President Joe Biden, speaking earlier in Poland, said Russia's involvement in Crimea was "a brazen military incursion" and its annexation of the territory was "nothing more than a land grab" by Moscow.
For a hastily arranged event, it was grandiose and full of pomp. This was partly to imbue the signing ceremony with as much majesty as possible, so even if it is disputed internationally, inside Russia it will be greeted as historical fact.
Certainly those present were jubilant. President Putin's address was interrupted by standing ovations. He made much of Crimea's special meaning for Russia, arguing not only that the Crimean people had the right to determine their own fate, but that he was correcting a "historical wrong", because when Crimea ended up in independent Ukraine after the collapse of the Soviet Union, Russia, as he put it, "felt it had been robbed".
Other parts of the address were troubling: Russia and Ukraine he said were not just neighbours but one nation, and Moscow would always protect the millions of Russian speakers there. And he still sees the new authorities in Kiev as an illegitimate puppet government under the control of radicals.
The Ukrainian foreign ministry said: "We do not recognise and never will recognise the so-called independence or the so-called agreement on Crimea joining the Russian Federation."
Ukraine's interim PM Arseniy Yatsenyuk said the Crimea crisis had moved from the political to the military stage.
Germany and France quickly condemned the Russia-Crimea treaty.
UK Prime Minister David Cameron said: "It is completely unacceptable for Russia to use force to change borders on the basis of a sham referendum held at the barrel of a Russian gun."
Mr Putin later appeared before crowds in Moscow's Red Square, telling them: "Crimea and Sevastopol are returning to... their home shores, to their home port, to Russia!"
He shouted "Glory to Russia" as the crowds chanted "Putin!"
The Ukrainian crisis began in November last year after pro-Moscow President Viktor Yanukovych abandoned an EU deal in favour of stronger ties with Russia. He fled Ukraine on 22 February after deadly protests.'Historical injustice'
Crimean officials say that, in a referendum held in the predominantly ethnic-Russian region on Sunday, 97% of voters backed splitting from Ukraine.
The EU and US have declared the vote illegal. Travel bans and asset freezes have been imposed on government officials and other figures in Russia, Crimea and Ukraine, but these have been largely dismissed as ineffectual in Russia.
In a televised address in front of both houses of parliament and Crimea's new leaders, Mr Putin said: "In the hearts and minds of people, Crimea has always been and remains an inseparable part of Russia."
At the scene
Nakhimov Square may not have been packed out for the broadcast of Vladimir Putin's speech but the numbers were decent and the mood good-humoured. Small children cut arcs in the air with the Russian tricolour as their parents' faces creased into smiles in the sunshine.
The striking thing was the relaxed mood. Security was minimal and nobody seemed bothered by the media presence now. Presumably supporters of union felt they had got their result and could breathe easy.
Afterwards families headed down to the nearby quays to photograph each other against the picturesque backdrop of the bay, tricolours in hand. The waterfront, scene of many tragic chapters in this city of sieges, is a happy place this afternoon.
The referendum had been legal and its results were "more than convincing", he said.
"The people of Crimea clearly and convincingly expressed their will - they want to be with Russia," he said, and were no longer prepared to put up with the "historical injustice" of being part of Ukraine.
Crimea was transferred from Russia to Ukraine while under Soviet rule in 1954.
Mr Putin criticised Ukraine's post-uprising leaders and those behind the unrest, saying they were "extremists" who had brought chaos.
He also praised the "courage, bearing and dignity" of Crimeans, and thanked all Russians for their "patriotic feeling".
The West, he said, had behaved "irresponsibly" in backing the uprising, and he denied Russia was interested in annexing more territory.
"Don't trust those who frighten you with Russia... we do not need a divided Ukraine" he said.
Russia "will of course be facing foreign confrontation," he said, adding: "We have to decide for ourselves, are we to protect our national interest or just carry on giving them away forever?"
The audience frequently applauded Mr Putin at length during his emotionally charged speech, and gave him a standing ovation.
President Putin, Crimea's Prime Minister Sergei Aksyonov, the region's Speaker Vladimir Konstantinov and the mayor of Sevastopol, Alexei Chaliy, then signed a treaty on making the Black Sea peninsula a part of Russia.
Earlier, Mr Putin had recognised Crimea as a sovereign state and approved a draft bill on its accession to the Russian Federation.
- 21 Nov 2013: President Viktor Yanukovych abandons an EU deal
- Dec: Pro-EU protesters occupy Kiev city hall and Independence Square
- 20-21 Feb 2014: At least 88 people killed in Kiev clashes
- 22 Feb: Mr Yanukovych flees; parliament removes him and calls election
- 27-28 Feb: Pro-Russian gunmen seize key buildings in Crimea
- 6 Mar: Crimea's parliament votes to join Russia
- 16 Mar: Crimea voters choose to secede in disputed referendum
- 17 Mar: Crimean parliament declares independence and formally applies to join Russia
The bill must now be approved by the constitutional court and then ratified by parliament.
The BBC's Richard Galpin in Moscow says the process is likely to be completed by the end of the week.
Western powers have roundly condemned Tuesday's treaty.
The UK was suspending "all bilateral military co-operation [with Russia] not subject to treaty obligations", Foreign Secretary William Hague told Parliament.
German Chancellor Angela Merkel said that the referendum, the declaration of independence and Crimea's "absorption into the Russian Federation" were "against international law".
French President Francois Hollande called for a "strong and coordinated European response" to the Russian moves.