Britain calls for de-escalation of tensions in Ukraine

British Saturday expressed "deep concerns" over the escalation of tensions in Ukraine, urging the world leaders to take diplomatic action to address the crisis in the eastern European country.

"I am deeply concerned at the escalation of tensions in Ukraine, and the decision of the Russian parliament to authorise military action on Ukrainian soil against the wishes of the Ukrainian government," Xinhua quoted Foreign Secretary William Hague as saying in a statement.

"This action is a potentially grave threat to the sovereignty, independence and territorial integrity of Ukraine. We condemn any act of aggression against Ukraine."

However, Russian President Vladimir Putin has not yet decided on the use of military force in Ukraine despite winning the green light from the upper house of parliament for such a move, presidential spokesperson Dmitry Peskov said Saturday.

"Now that the Federation Council, upper house of parliament, adopted the relevant decision, the president has received the full array of means needed for settling the situation both in terms of using troops and in terms of making a decision on the head of our diplomatic mission in the United States," Peskov told a TV channel.

Putin had not yet made either decision, and he would make decisions depending on how the situation evolves, the spokesperson said.

Hague said that Britain has summoned the Russian ambassador to the British Foreign Office to register its "deep concerns".

The British foreign secretary spoke to his Russian counterpart Sergei Lavrov Saturday to urge steps to calm the "dangerous situation" in Ukraine, according to the British Foreign Office.