Gunfire at a Ukrainian military facility in the capital of separatist Crimea has killed one serviceman and a member of a local self-defence brigade.

Details of the violence in Simferopol were sketchy, but the outburst underlined the high tensions over Crimea's weekend vote to split from Ukraine and join Russia.

The development came after Russian President Vladimir Putin signed an agreement to annex Crimea, which has a majority ethnic Russian population and is home to the Russian Black Sea under a lease with Ukraine.

Police spokeswoman Olga Kondrashova said two other people were wounded in the gunfire at a remote-sensing and navigational facility.

Vladislav Seleznev, a spokesman for the Ukrainian armed forces in Crimea, said the facility was stormed by unknown armed men and that one serviceman was killed and another wounded.

Ukrainian Prime Minister Arseniy Yatsenyuk has blamed Russia, saying the storming of the military facility showed that the dispute "has gone from the political stage to the military by the fault of the Russians".

A local news agency recently formed by pro-Russian Crimean authorities gave a different account, saying that snipers fired on self-defence units that had arrived to check out a report of armed men and that one of the self-defence brigade was killed.

Since Crimea's tensions soared three weeks ago, units of uniformed men without insignia have appeared, purportedly local residents defending their territory.

Russian forces effectively took control of Crimea after Ukraine's pro-Russia President Viktor Yanukovych fled the country in the wake of months of protests and sporadic bloodshed.

Crimeans overwhelmingly voted in a referendum on Sunday to seek to join Russia, which it had been part of for centuries until Soviet leader Nikita Khrushchev transferred it to Ukrainian jurisdiction in 1954.

Mr Putin signed the agreement with Crimea's prime minister and parliament speaker following a televised address to the nation, in which he vigorously defended Crimea's vote as a restoration of historical justice.

The agreement has to be endorsed by Russia's Constitutional Court and ratified by both houses of parliament to take effect. Those steps are considered formalities.

Mr Putin has accused the West of encouraging unrest in Ukraine in order to break its historic ties with Russia, and dismissed Western criticism of the Crimean vote as illegitimate.

He described the move as correcting past injustice and a necessary response to what he called Western encroachment upon Russia's vital interests.

In an emotional 40-minute speech that was televised live from the Kremlin, Mr Putin said "in people's hearts and minds, Crimea has always been an integral part of Russia".

He dismissed Western criticism of Sunday's Crimean referendum - in which residents of the strategic Black Sea peninsula overwhelmingly backed breaking off from Ukraine and joining Russia - as a manifestation of the West's double standards.

At the same time, the Russian leader said his nation did not want to move into other regions of Ukraine, saying "we don't want division of Ukraine".

Thousands of Russian troops have been massed along Ukraine's eastern border for the last few weeks. Russia says it was for military training while the US and Europe view the troops as an intimidation tactic.

Mr Putin argued that months of protests in the Ukrainian capital that promptedMr Yanukovych to flee to Russia had been instigated by the West in order to weaken Russia.

He cast the new Ukrainian government as illegitimate, driven by radical "nationalists, neo-Nazis, Russophobes and anti-Semites".

The speech came just hours after he approved a draft bill for the annexation of Crimea, a key move in a flurry of steps to formally take over the Black Sea peninsula.

To back his claim that Crimea's vote was in line with international law, Mr Putin pointed to Kosovo's independence bid from Serbia - supported by the West and opposed by Russia - and said Crimea's secession from Ukraine repeats Ukraine's own secession from the Soviet Union in 1991.

He denied Western accusations that Russia invaded Crimea prior to the referendum, saying Russian troops were sent there in line with a treaty with Ukraine that allows Russia to have up to 25,000 troops at its Black Sea Fleet base in Crimea.

Mr Putin had previously warned that he would be ready to use "all means" to protect Russian speakers in eastern Ukraine, and Russia has built up its forces alongside the border between the two countries, raising fears of an invasion.

Ukraine's prime minister Arseniy Yatsenyuk said in a televised statement that Ukrainian law-enforcement agencies have gathered "convincing evidence of the participation of Russian special services in organising unrest in the east of our country".

The hastily called Crimean vote was held just two weeks after Russian troops overtook the Black Sea peninsula, blockading Ukrainian soldiers at their bases.

The West and Ukraine described it as illegitimate and being held at gunpoint. But residents on the peninsula voted overwhelmingly to join Russia.

The United States and the European Union have announced asset freezes and other sanctions against Russian and Ukrainian officials involved in the Crimean crisis. It has also had its G8 membership suspended.

In his speech, Mr Putin made it clear that Russia would not be deterred by Western sanctions, and asked China and India for their support.