The "Normandy" group is set to conduct a follow up on the peace process in Ukraine. Amnesty International has said it has evidence the rebels carried out execution-style killings of Ukrainian soldiers.

Germany said on Thursday it hoped for a meeting of the "Normandy" group in the coming day, referring to itself, France, Russia, and Ukraine.

"A meeting of the Normandy group soon would be important, we must stick to the implementation of the Minsk deal. A meeting can hopefully take place early next week," said a government official.

The meeting of the four nation's foreign ministries will act as a follow-up on the fragile Ukrainian ceasefire made in February after nearly a year of bloody war in the east between government forces and pro-Russian rebels.

"I will be in Berlin (on Monday) evening," French Foreign Minister Laurent Fabius told the press, without specifying that it would be a meeting about the ongoing conflict. Speaking after talks with his Ukrainian counterpart Pavlo Klimkin in Paris, Fabius said Ukraine's President Petro Poroshenko is due to visit France later in April.

"There has been some progress on the ground in implementing the package of February 12 Minsk measures, despite too many violations, where pulling back heavy weapons in concerned," Fabius added.

Amensty says it has evidence of "war crimes"

The truce appeared to be largely holding despite isolated deadly clashes and the slow roll back of heavy weapons. Amnesty International said Thursday it had evidence that the separatists in east Ukraine had executed several captured government soldiers, in gross violation of international law.

The human rights group claimed that it had seen footage showing four Ukrainian soldiers - now confirmed dead - being interrogating by the rebels. Pictures showing bullet wounds to the soldier's heads illustrated that they had died as the result of execution-style killings, Amnesty said.

"The torture, ill-treatment and killing of captured, surrendered or wounded soldiers are war crimes," Denis Krivosheev, Europe and Central Asia deputy director at Amnesty International, said in the group's statement.

Hundreds of Ukrainian troops are believed to have been captured by rebel forces over the course of a year-long war that has claimed more than 6,000 lives.

es/jil (AP, AFP, Reuters)