Speaking in Berlin on Tuesday, Germany's foreign minister said, "The fact that the number of ceasefire violations in eastern Ukraine has increased rather than decreased during Christmas is not a very good development towards the end of the year."

Steinmeier said there was a danger of war breaking out both at the beginning and the end of 2015. "Thanks to the Minsk agreement, we were successfully able to avoid it," he said. 2015 also witnessed important developments in military de-escalation and withdrawal of weapons, the Social Democrat added.

However, many important questions remained to be answered, he said. "The truce is becoming more and more fragile. Even now there is no consensus over a special law for local elections in parts of Donbass controlled by the separatists," Steinmeier said, adding that people in the area had suffered many human rights violations and that the humanitarian situation was worsening.

The minister called upon all sides to set prisoners and hostages free, to allow rescue organizations to register in the area and to restore water supply to the Donbass region.

Germany, France and other countries of the European Union have been trying to restore peace to eastern Ukraine after a conflict that began in March 2014, with Russia's annexation of the Crimean peninsula. Relations with Russia have nosedived since then, with the EU imposing sanctions on Moscow for allegedly supporting anti-Kyiv separatists in eastern Ukraine.

Kyiv signed a peace pact with separatists earlier this year, in the presence of leaders from Germany, France and Russia. However, several aspects of the agreement are yet to be implemented.

mg/jil (Reuters, dpa)