France said on Wednesday that the Ukraine ceasefire deal signed last week "was not dead" and it would do "everything to keep the agreement alive" despite the capture of a key town by pro-Russian
forces.

"We will continue, we know we have some problems, we know that not everything has been settled," said French government spokesman Stephane Le Foll. "But between the situation just before the Minsk agreement and the situation now… there has been progress.

French President Francois Hollande will speak on the phone with his German, Russian and Ukrainian counterparts on Wednesday evening, a French government spokesman said.

The call with German Chancellor Angela Merkel, Russian President Vladimir Putin and Ukraine's President Petro Poroshenko follows the capture of the key strategic town of Debaltseve in eastern Ukraine by pro-Russian rebels, which has threatened the tentative ceasefire agreement signed last week.

Speaking on Tuesday France's Foreign Minister Laurent Fabius said that "fundamental" parts of the ceasefire deal in Ukraine were not being followed, despite a reduction in fighting between government and rebel forces.

"We can say the ceasefire is being generally respected, but there are two major 'buts'," Fabius told the French parliament.

He said "extremely heavy fighting" was continuing around the contested town of Debaltseve in eastern Ukraine, which pro-Russian rebels claim was not covered by the ceasefire agreement which came into force on Saturday.

Nor has there been a withdrawal of heavy weapons as planned, said Fabius.

"Clearly, these two aspects are fundamental."

France and Germany led the way in pushing for the truce deal in a bid to end the 10-month conflict that has claimed some 5,500 lives.

"Between the agreement on paper and the agreement on the ground, there are clearly differences," said Fabius.