Ukraine crisis will cost Russia, says White House

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 endorse joining Russia.

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

US Deputy National Security Advisor Ben Rhodes said the Obama administration would introduce measures to impose "a cost" on Russia for its "intervention" in Crimea.