France, Germany, and Kyiv have cast doubt on whether a four-way summit on Ukraine will be held next week in Kazakhstan's capital.
Ukrainian President Petro Poroshenko said late last month that he would meet with Russian President Vladimir Putin, French President Francois Hollande, and German Chancellor Angela Merkel in Astana on January 15 in an attempt to end the conflict in eastern Ukraine.
Asked about the planned meeting, Merkel's spokesman said on December 5, "I can't say yet if and when such a meeting will take place."
Steffen Seibert said such a meeting "only makes sense" if progress is made on "the full implementation of the Minsk peace accord and a genuine and lasting cease-fire, a contact line between areas controlled by Ukraine and rebels, and a withdrawal of heavy weaponry."
"Such things must be prepared in advance," he added.
In an interview with France Inter radio in Paris, President Francois Hollande said, "I am going to Astana on January 15 on one condition -- one condition -- that there can be progress."
"If it's just to meet and talk without any breakthrough, there's no point. But I think there will be some [breakthroughs]," he said.
Poroshenko said the talks would take place if "we manage to produce a draft [of an] agreed document" before January 15.
The Kremlin has made no official statement on the meeting.
The European Union, United States, and other countries have imposed sanctions on Russia over its annexation of Crimea in March and its support for the separatists, whose conflict with government troops has killed more than 4,700 people in eastern Ukraine since April.
Hollande said he wants the sanctions to be lifted if Moscow respects Ukraine's sovereignty.
The French president called on Putin to respect Ukraine's territorial integrity, to stop supporting pro-Russian separatists in the country's east, and to allow Kyiv to develop economic relations with the West.
He also said Putin "doesn't want to annex eastern Ukraine, he told me that."
Meanwhile, Germany’s Vice Chancellor Sigmar Gabriel told the Bild am Sonntag newspaper on January 4 that some "forces" in Europe and the United States wanted sanctions to cripple Russia, which would "risk a conflagration."
"We want to help get the Ukraine conflict resolved, but not to push Russia to its knees," he added.
The comments came as Foreign Ministry representatives from Ukraine, Russia, France, and Germany met in Berlin on January 5 in an attempt to advance efforts to restore peace in eastern Ukraine.
The head of the Ukrainian Foreign Ministry's department of politics and communications, Oleksiy Makeyev, represented Kyiv.
Russia sent Viktor Sorokin, who heads the Foreign Ministry department responsible for relations with Ukraine.
Makeyev said on January 4 that participants would present their plans to further the implementation of an accord on a cease-fire and steps toward peace that was signed in Minsk on September 5.
More than 1,300 people have been killed since the cease-fire agreement, but fighting abated somewhat last month.
On January 8, Ukrainian Prime Minister Arseniy Yatsenyuk is due to meet with Merkel in Berlin.
With reporting by Reuters, TASS, RIA Novosti, and Interfax