Ukraine.

The newly appointed head of Ukraine's navy has sworn allegiance to the Crimea region, in the presence of its unrecognised pro-Russian leader.

Rear Admiral Denys Berezovsky was only made head of the navy on Saturday, as the government in Kiev reacted to the threat of Russian invasion.

Russia's troops have been consolidating their hold on Crimea, which is home to its Black Sea Fleet.

Nato's chief has asked Russia to withdraw its forces to its bases.

"We call on Russia to de-escalate tensions... to withdraw its forces to its bases and to refrain from any interference elsewhere in Ukraine," Anders Fogh Rasmussen said, speaking in Brussels.

Ukraine was a "valued partner" for Nato and should be allowed to determine its own future, he said.
US Secretary of State John Kerry warned Moscow might be ejected from the G8 for its actions but his German counterpart, Frank-Walter Steinmeier, argued for Moscow's continuing membership.

"The format of the G8 is actually the only one in which we in the West can speak directly with Russia," he told the public broadcaster ARD.

US President Barack Obama called Russian troop deployments a "violation of Ukrainian sovereignty".
'Brink of disaster'

Ukraine has ordered a full military mobilisation in response to Russia's build-up of its forces on the Crimean peninsula. Prime Minister Arseniy Yatsenyuk has warned the country is "on the brink of disaster".

In Crimea, Ukrainian soldiers faced off with Russian soldiers surrounding their bases on Sunday while the Russian army was said to be digging trenches on the border with mainland Ukraine.

The UK has joined the US, France and Canada in suspending preparations for a summit of the G8 in Russia in June. Nato, of which Ukraine is not a member, is conducting emergency talks.

Admiral Berezovsky appeared in Sevastopol before cameras alongside Sergiy Aksyonov, the pro-Russian politician elected by Crimea's regional parliament as local prime minister.

Mr Aksyonov announced he had given orders to Ukrainian naval forces on the peninsula to disregard any orders from the "self-proclaimed" authorities in Kiev.

Sunday, he said, would go down in history as the birthday of the "navy of the autonomous republic of Crimea".

The admiral then pledged to "strictly obey the orders of the supreme commander of the autonomous republic of Crimea" and "defend the lives and freedom" of Crimea's people.

Admiral Berezovsky was later sacked by interim Ukrainian Defence Minister Ihor Tenyukh and a treason case launched against him.

Ukraine's Ukrainska Pravda newspaper reports that the admiral was speaking before the "numerous cameras of predominantly Russian TV channels".

Earlier, Ukrainian naval officers found their headquarters in Sevastopol occupied by Russian troops and were unable to go to work.

Separately, Ukraine withdrew coast guard vessels from two ports in Crimea and moved them to other bases in the Black Sea and Sea of Azov on Sunday.

Several Ukrainian army bases were surrounded by Russian troops on Sunday but there were no reports of clashes despite the refusal of Ukrainian soldiers to open their gates.

Ukrainian armed forces dispatched to Crimea have switched to the side of local authorities and are expected to take military oath soon, Russian news agencies report.

Facts you need to know about Crimea and why it is in turmoil

“Today the majority of the Ukrainian armed forces deployed in Crimea passed to the side of the authorities of the Crimean autonomous region. The transition was absolutely peaceful, without a single shot fired either by the military or by the forces of self-defense,” an unnamed source told RIA Novosti news agency.

The source added that some of the servicemen also ran away, while some submitted letters of resignation.

The local military have not been paid for many months, the source also told RIA Novosti.

Newly appointed Navy Chief rear admiral Denis Berezovsky has sworn allegiance to the people of Crimea, the news agency reported.

“I, Berezovsky Denis, swear allegiance to the Crimean people and pledge to protect it, as required by the [army] regulations,” he said.

Earlier, Ukrainian troops in Crimea were said to be resigning on a massive scale. Living quarters, weapons and ammunition have all been left under the protection of the so-called ‘self-defense forces.’

Letters of resignation have been coming in since early morning, as the self-defense forces continue to preserve order on the streets of Simferopol, RIA Novosti said citing own reporters on the ground.

Since Thursday, the city’s Supreme Council and a number of other buildings have been occupied and guarded by the self-defense forces run by the local population.

Crimea’s deputy prime minister, Rustam Temirgaliev, announced that the Ukrainian armed forces have all but surrendered their military capabilities and that no active units remain in the Crimea.

"The entire Ukrainian armed forces stationed on the Crimean territory have been blocked," Interfax reported him as saying. "The self-defense forces have taken control of the landing strips of all the Crimean airports and airfields."

The deputy PM said that that the region’s security services and emergency services now report to the local government.

Crimeans began protesting after the new self-imposed government in Kiev introduced a law abolishing the use of other languages for official documents in Ukraine. More than half the Crimean population are Russian and use only this language for their communication. The residents have announced they are going to hold a referendum on March 30 to determine the fate of the Ukrainian autonomous region.