BRUSSELS. The EU and US have joined Ukraine’s government in condemning as "illegal” a move by the Crimea region to set up a referendum to join Russia.

The EU, meeting in Brussels, threatened "serious consequences” if Russia did not act to de-escalate the crisis.

Crimean MPs earlier set a date of 16 March for a vote on the referendum.

Russian troops took de facto control of Crimea, whose population is mostly ethnic Russian, in the wake of the fall of Ukraine’s pro-Moscow president.

The Crimean parliament on Thursday said it had decided "to enter into the Russian Federation with the rights of a subject of the Russian Federation”.

It said it had asked Russian President Vladimir Putin "to start the procedure”.

Before the Brussels summit, some EU members - led by Germany - had indicated they preferred mediation with Russia to try to solve the crisis, rather than any stronger measures.

But the BBC’s Matthew Price in Brussels says the Crimean MPs’ move has clearly toughened the line taken by the EU.

In a press conference after the talks, German Chancellor Angela Merkel and EU Council President Herman Van Rompuy both said the Crimean referendum was contrary to the Ukrainian constitution and therefore illegal.

The EU said it was suspending talks with Moscow on easing travel restrictions on Russians entering the EU.

It said that if Russia did not move to de-escalate the situation quickly, it would "decide on additional measures, such as travel bans, asset freezes and the cancellation of the EU-Russia summit”.

The EU statement said that "any further steps by the Russian Federation to destabilise the situation in Ukraine would lead to severe and far-reaching consequences... which will include a broad range of economic areas”. The US had earlier issued visa restrictions on a number of unnamed Ukrainian and Russian officials and individuals "to deny visas to those responsible for, or complicit in, threatening the sovereignty and territorial integrity of Ukraine”.

In a televised address, Ukraine’s Interim President Olexander Turchynov denounced the referendum as "illegitimate and unnecessary, it contradicts the will of the Ukrainian people”.

He cited Article 73 of the Ukrainian constitution which says issues relating to borders must involve a "referendum across the whole of Ukraine”.

Mr Turchynov said: "Ukraine’s territory within the boundaries recognised by the whole world is inviolable and sovereign.”

But Crimea’s First Deputy PM Rustam Temirgaliev said Crimea viewed the new authorities in Kiev as illegitimate and that Crimea was now in Russia.