BERLIN - The foreign ministers of Germany, France, Russia and Ukraine on Monday urged a meeting of the contact group on Ukraine to make progress on implementing the September Minsk peace deal.

In a joint statement, the ministers called on the contact group of Ukraine, Russia, and the OSCE to hold a higher-level meeting in the coming days in Kazakhstan to make progress on the full implementation of the Minsk agreements, including the creation of relevant conditions for an effective cease-fire.

Ukrainian President Petro Poroshenko has invited the leaders of Russia, France and Germany to talks over the Ukraine crisis in Astana on Thursday.

But German Chancellor Angela Merkel has left it open as to whether the four-way summit would be held as proposed.

She noted that a substantial narrowing of differences between conflict parties is needed for the meeting to take place.

The ministers affirmed their strong commitment to a swift and comprehensive peaceful solution of the current crisis, including a sustainable political process, according to a joint statement issued after their talks.

They reaffirmed that the basis of a solution to the conflict lies in the Minsk agreements that have to be implemented by all sides in their entirety, and reiterated the necessity to fully respect the regime of quiet.