French President Francois Hollande and German Chancellor Angela Merkel on Friday said any country that failed to respect the Minsk agreements would face sanctions, recalling the need to fully impose the ceasefire deal as fighting escalated in eastern Ukraine.

"Any country that would break Minsk agreement on Ukraine would face sanctions but our intention is not to impose sanctions," Hollande said in a joint news conference with Merkel.

"With the (German) Chancellor, we have never stopped speaking since the (September 2014) Minsk agreements and we are more convinced than ever that they must be applied -- all the agreements, nothing but the agreements," he added.

The two leaders, who brokered a peace deal to help resolve the Ukrainian crisis, reinforced diplomatic efforts "to reach as soon as possible full implementation of the ceasefire."

After fresh fighting between militants and Ukrainian forces breached the ceasefire accord, Merkel noted that imposing peace in Ukraine would be a "difficult process."

"The peace process in Ukraine will take time. It's hard (but) I do not worry about the future either," Merkel said.

Merkel told reporters that the European Union "could raise the issue of sanctions" if the Minsk deal is violated.

Negotiated by France, Germany, Russia and Ukraine last Thursday, the ceasefire in Ukraine came into force on Sunday. It is aimed at ending fighting in Ukraine's eastern regions, continuing the process of prisoners swapping and stopping the arming of separatists.

Top diplomats from France, Germany, Russia and Ukraine are expected to meet in Paris next week to see how to push through the ceasefire agreement.

More than 5,600 people have been killed in fighting in Ukraine since April 2014 last year.