The leaders of France, Germany, Russia and Ukraine agreed in a telephone call on Thursday that preliminary accords to extend a pull-back of weapons in east Ukraine should be signed quickly, French President Francois Hollande's office said.
Ukraine and pro-Russian separatists agreed earlier this week that tanks and smaller weapons systems should also be withdrawn in addition to heavy artillery, as was previously agreed.
The leaders of the four countries "want the agreements to be signed as soon as possible", Hollande's office said in a statement following the telephone call lasting over two hours.
Under a ceasefire agreement brokered in Minsk in February, weapons of over 100 mm caliber are meant to have already been withdrawn, but both sides accuse the other of continuing to use heavy artillery and casualties are reported almost daily.
More than 6,500 people have been killed since the conflict broke out in eastern Ukraine in April last year.