Talks on the crisis in Ukraine have led to an agreement to pull back heavy weaponry from a demarcation line defined in last year’s Minsk agreement.
German Foreign Minister Frank-Walter Steinmeier brokered the deal with his counterparts from France, Russia and Ukraine during talks in Berlin.
“A lot depends on the question if that what we have agreed on will not only remain printed paper, but will also change the situation on the ground,” Mr Steinmeier said.
In a joint statement released by the German foreign ministry, the ministers noted “with serious concern” that fighting in eastern Ukraine had severely escalated, causing the loss of many human lives.
“This must stop immediately and the regime of quiet must be restored,” the statement said.
They called on signatories of the Minsk peace plan to meet in the coming days to implement the ceasefire and withdrawal of heavy weapons.
Kiev and Moscow blame each other for failing to implement a ceasefire agreed in Minsk last September to end the conflict in eastern Ukraine, where more than 4,700 have died in fighting between the Ukrainian army and pro-Russian rebels.
The development comes after the Ukrainian President claimed more than 9,000 Russian soldiers are currently backing up pro-Moscow fighters in the separatist east of the country.
In a speech at the World Economic Forum in Davos, Petro Poroshenko said Russian troops were backed by a range of heavy weapons including tanks and artillery systems.
“We have more than 9,000 troops of the Russian Federation on my territory, including more than 500 tanks and heavy artillery and armed personnel carriers,” he said.
“If this is not aggression, what is aggression?”
Russian Foreign Minister Sergei Lavrov challenged Kiev to “present the proof”.
US officials later cranked up the diplomatic pressure on Russia with Secretary of State John Kerry calling Russia’s actions “a blatant land grab”.