Ukrainian President Petro Poroshenko has told EU foreign policy chief Catherine Ashton he's ready to convene new European-mediated crisis talks with separatist leaders and Russian officials July 5.
Poroshenko's office said July 4 that "Ukraine has proposed a place and time for the meeting and is waiting the other party's confirmation."
A "contact group" is to work out conditions for a cease-fire.
The group includes a former Ukrainian president, Moscow's ambassador to Kyiv, and a high-ranking official from the OSCE.
ITAR-TASS reports that French President Francois Hollande and German Chancellor Angela Merkel also held joint telephone conversations with Poroshenko on July 4
Hollande and Merkel "called for soonest fulfilment of the agreements" reached by France, Germany, Russia, and Ukraine in Berlin June 2 to relaunch the peace process.
Meanwhile, a spokesman for the Ukrainian army's operation in eastern Ukraine says government forces killed 150 militants near the town of Mykolayivka, outside of Slovyansk in Donetsk region.
Live Blog: Ukraine In Crisis
Oleksiy Dmytrashkivskiy said one Ukrainian soldier was killed and another four injured in the fighting, which began on the evening of July 3 and was aimed at sealing off the town.
Separately, residents of Donetsk city report hearing sounds of fighting involving heavy artillery overnight.
'Air Space Violated'
A city administration spokesman told reporters the fighting was near the villages of Peski and Karlivka.
There are no immediate reports of casualties.
Also on July 4, Kyiv said it is prepared to open fire on Russian helicopters if they violate its airspace.
Ukrainian National Security and Defense Council Secretary Andriy Parubiy told a press conference that Ukraine has registered violations of its airspace by Russian helicopters over the past day and is ready to open fire on any aircraft continuing to do so.
A unilateral cease-fire declared by Poroshenko expired on June 30 after being violated repeatedly by pro-Russian separatists.
In other news, the head of the separatist Luhansk People's Republic,Valery Bolotov, has dismissed his administration.
A statement on the self-declared republic's website said Bolotov had appointed Marat Bashirov as his acting prime minister, and Dmytro Semenov and Vasyl Nikitin as acting first deputy prime ministers.
No reasons for the dismissal of the former administration were given.