Ukraine's president and opposition have agreed to initial a deal to resolve their bloody standoff, the presidency announced on Friday after the deadliest day in a three-month crisis left more than 60 people dead.

"The parties agreed on the initialling of an agreement to resolve the crisis," the presidency said in a statement, adding that the sides were expected to sign the agreement at 1000 GMT.

The agreement, according to the Ukraine presidency, would see the country revert to the 2004 constitution within 48 hours and a formation of a coalition government within 10 days, privately-owned Ukrainian 1+1 channel said.

The crisis in Ukraine flared in November when President Viktor Yanukovych declined to sign an EU integration deal in favour of closer ties with historical master Russia, and has evolved into a Cold War-style standoff between Moscow and the West over the future of the strategic nation sandwiched between them.

Negotiations mediated by the German and Polish foreign ministers to broker an agreement between the embattled Yanukovych and the opposition -- described as "very difficult" by a German source -- broke up early Friday after some nine hours.

Thursday's bloodbath in Kiev came as the European Union agreed to impose sanctions on Ukrainians with "blood on their hands", though it left the door open to a political deal by naming no names.

The United States threatened to follow suit.

Yanukovych late Thursday appeared ready to concede to one of the protesters' main demands by suggesting to visiting EU dignitaries that he may be ready to hold early elections.

German Chancellor Angela Merkel, meanwhile, spoke to Presidents Barack Obama of the United States and Vladimir Putin of Russia -- who have bickered openly over the crisis, which has pitted the ex-Soviet country's future between Russia and the West -- by telephone.

All three called for a halt to the bloodshed that has escalated since Tuesday.

Opposition medics said more than 60 protesters had been shot dead by police on Thursday alone. Kiev authorities, for their part, put the death toll from three days of violence at 75.