Ukrainian President Petro Poroshenko said the agreement would be signed by August 3 and implemented within 10 days.
"We will work to ensure the signing of the agreement… and we will insist on it, it is the main condition of safety of the citizens, including those in Mariupol. Once the agreement is implemented, we will withdraw our weapons less than 100mm in caliber, because the heavy weaponry has already been withdrawn," Lysenko said at a briefing.
Lysenko stressed that the withdrawal must be "mutual," and that militias in southeastern Ukraine must not ignore the requirement.
Ukraine's southeast was engulfed in a conflict beginning April 2014, when Kiev launched a military operation to suppress local militias dissatisfied with the country’s new government coming to power following a February 2014 coup.
In mid-February, Kiev and the breakaway republics of Donetsk and Luhansk signed a ceasefire agreement after Normandy Quartet negotiations in the Belarusian capital, Minsk. However, the warring sides have since repeatedly accused each other of violating the truce.