EU Leaders Say Ukraine Rivals Must Turn 'Words into Deeds'

European Union president Herman van Rompuy welcomed an agreement signed Friday by Ukraine's leader and the opposition to end a deadly standoff but said it must be followed by concrete action.

"The agreement is a necessary compromise in order to launch an indispensable political dialogue that offers the only democratic and peaceful way out of the crisis that has already caused too much suffering and bloodshed on all sides," he said in a statement. "It is now the responsibility of all parties to be courageous and turn words into deeds for the sake of Ukraine's future."

Meanwhile, French president Francois Hollande called for Ukraine's government and opposition to fully and quickly implement the deal.

"After the unacceptable, intolerable and unjustifiable violence that plunged Ukraine into mourning in recent days, the president calls for the full and timely implementation of the deal that has just been signed," Hollande said in a statement.

French Foreign Minister Laurent Fabius also welcomed the deal as an "exit from the crisis", saying the negotiations that led to it took place in a "terrifying atmosphere".

"It's the best that we could have hoped for," Fabius told reporters on a visit to Beijing, having left Kiev to travel to China.

"It's the exit from the crisis. In any case everything is set up for that. It was very hard to reach agreement, because it needed hours and hours of negotiations: more than 10 hours with President Yanukovych, about the same with the representatives of the opposition, and in a terrifying atmosphere as there were dozens of dead," he added.

Yanukovych, he said, was "used to power, he doesn't share it", adding the government in Kiev was known to be corrupt. For its part the opposition "always wanted more", he said, while the demonstrators on Independence Square wanted Yanukovych to step down.

"Sometimes the talks were interrupted because there was a phone call. And it was Joe Biden from the U.S., or X or Y."

It was excellent news, Fabius said, adding: "Europe was very useful in dealing with this situation... everyone helped, including the Russians."

But he warned that Ukraine's economic situation remained appalling, and that the agreement still needed to be implemented.

British Prime Minister David Cameron said the deal between Ukraine's embattled president and the opposition was a real chance to stop the "downward spiral into the nightmare" otherwise facing the country.

Cameron said the violence witnessed in Kiev this week had "no place in 21st century Europe".

"I welcome today's agreement which offers a real chance to end the bloodshed and to stop the downward spiral into the nightmare that is facing Ukraine and her people," Cameron said in a statement.

"It should foster a lasting political solution to the crisis and president Yanukovych, his administration and the opposition must all get behind this deal and deliver it according to the timetable set out."

Cameron said he hoped the deal "will restore calm to the streets of Kiev and across the country".

"Such scenes of carnage are truly shocking and have no place in 21st century Europe."

Cameron has spoken to Russian President Vladimir Putin, German Chancellor Angela Merkel and Polish Prime Minister Donald Tusk in the last 24 hours.

"We all support this deal and want to see it work," Cameron said.

"And working with other European partners and the United States, we will do all we can to ensure it succeeds."