Crimea's Tatars will on Saturday hold a vote on whether to push for self-rule in their historic homeland following its annexation by Russia.

Ethnic Tatars from all over Crimea convened in the town of Bakhchisaray for an emergency Qurultai, or congress, to decide on the fate of the Muslim community of about 300,000 people on the Black Sea peninsula.

Russia has absolutely no intention of ordering its armed forces to cross over the Ukrainian border and the divisions between Moscow and the West on the crisis are narrowing, Russian Foreign Minister Sergei Lavrov said Saturday.

"We have absolutely no intention and no interests in crossing the Ukrainian border," Lavrov told Russian state television in an interview, appearing to firmly rule out an invasion of mainland Ukraine after Moscow's seizure of Crimea.

Russian President Vladimir Putin called his American counterpart Barack Obama Friday to discuss a U.S. proposal for a diplomatic end to the Ukraine crisis while insisting to the United Nations that Moscow had "no intention" of further military action.

The White House said Putin phoned Obama following a bid presented to Russian Foreign Minister Sergei Lavrov by U.S. Secretary of State John Kerry earlier this week.

Wary of their powerful neighbor Russia, the Baltic states of Lithuania and Latvia plan to double defense spending while Estonia will maintain its strong level after watching Moscow take over Crimea.

The three countries of 6.3 million people will mark on Saturday a decade since joining the NATO military alliance, a move seen as a bulwark against unwanted Russian overtures.

Two influential U.S. lawmakers urged President Barack Obama on Friday to send lethal military aid to Ukraine, arguing that Russian aggression should be a "wake up call" to the West.

The new government in Kiev has sought military assistance from the United States after Russian forces invaded Ukraine's Crimean peninsula and absorbed it, sending regional tensions soaring.

U.S. President Barack Obama in an interview aired Friday said Russia must "move back" its troops from the Ukraine border and start negotiating.

Obama told CBS News that Russian President Vladimir Putin's decision to assemble forces on the border may "simply be an effort to intimidate Ukraine, or it may be that they've got additional plans."

Ukraine's race to succeed ousted Russian-backed president Viktor Yanukovych heated up Friday after his arch-rival Yulia Tymoshenko joined a crowded field of contenders ready to tighten Kiev's embrace of the West.

The charismatic but hugely divisive Tymoshenko's decision to contest the May 25 poll encapsulates the spectacular scale of change that has swept over the culturally splintered nation since it was first hit by waves of deadly pro-Europe protests four months ago.

The U.S. House and Senate overwhelmingly adopted separate Ukraine aid packages Thursday, including sanctions against Russians, easing a weeks-long impasse on how American lawmakers can help Kiev's new government.

Senators were almost unanimous in a voice vote to pass their legislation which offers $1 billion in loan guarantees pledged to Ukraine by President Barack Obama, and punishes Russian officials and others for their role in Moscow's Crimea aggression.

Hundreds of Ukrainian far-right nationalists rallied outside the parliament building in Kiev Thursday night, smashing windows and demanding the interior minister's resignation, days after police shot dead one of their leaders.

Elite police on Monday killed Oleksandr Muzytchko, the regional leader of Pravy Sektor (Right Sector), in a shootout that erupted during a raid to arrest him in the western city of Rivne.

British euroskeptic leader Nigel Farage on Thursday accused the EU of having "blood on its hands" by backing uprisings in Ukraine and Syria.

The UK Independence Party chief faced criticism in Britain for his comments, with Deputy Prime Minister Nick Clegg saying Farage was siding with Russian President Vladimir Putin.