West voices alarm on Crimea, calls on Russia to respect Ukraine sovereignty
* Ukraine says Russia sending extra troops to Crimea
* Putin proposes sending armed forces to Crimea
* France, Britain, Germany urge for de-escalation
* Calls come after Obama warns Russia against intervention
The West expressed alarm on Saturday over fast-moving developments in Ukraine's Crimea, urging all sides to avoid further escalation and calling on Russia to respect Ukraine's sovereignty.
A week after violent protests forced Russian-backed President Viktor Yanukovich to abandon power in Kiev, Ukraine's new leaders say Russia is trying to take control of the southern Crimea region, which has a majority ethnic Russian population.
France, Britain and Germany issued calls for de-escalation in Crimea hours after U.S. President Barack Obama warned that military intervention in the region would be deeply destabilising and "carry costs".
"France is extremely concerned by the reports from Crimea, which describe significant troop movements," French Foreign Minister Laurent Fabius said in a statement. "We call on the parties to abstain from acts that could raise tensions and affect Ukraine's territorial unity."
No bloodshed followed Yanukovich's ouster, but Ukraine's new leadership faces a challenge in Crimea, which was part of Russia until 1954.
Ukrainian Prime Minister Arseny Yatseniuk accused Russia on Saturday of sending thousands of troops to the area.
Armed men wearing combat uniforms with no identification have taken control of two airports in the area and have taken over the regional parliament in what Kiev describes as an occupation by Moscow's forces.
Crimea's pro-Russia prime minister has put himself in charge of all military forces, police and other security services in the region. He has also appealed to Russian President Vladimir Putin for assistance in "guaranteeing peace and calm" there.
Putin has asked the upper house of parliament to approve sending armed forces to Ukraine's Crimea region, citing a threat to the lives of citizens of Russia.
British Foreign Secretary William Hague, who travels to Ukraine on Sunday to hold talks with the new leadership, urged his Russian counterpart to act to ease tensions.
In a tweet, Hague added he had spoken to German Foreign Minister Frank-Walter Steinmeier and discussed the need for international diplomatic action to address the crisis.
Earlier, Steinmeier called developments in Crimea over the past few hours dangerous and urged Russia to explain its intentions.
"The situation in Crimea in particular has become considerably more acute. Whoever pours more oil onto the flames now, with words or actions, is consciously aiming for further escalation of the situation," he said.
"Everything Russia does in Crimea must be in keeping with the sovereignty and territorial integrity of Ukraine, and treaties on Russia's Black Sea fleet," he said.
Steinmeier said European leaders must confer swiftly in order to agree a common position of the European Union.
Russia says any movements by its military in Crimea are in line with agreements with Ukraine in the lease of a naval base in the port city of Sevastopol, and Moscow has accused Kiev of trying to destabilise the Black Sea peninsula.