Pro-Russia rebels in eastern Ukraine say they will observe a ceasefire until Friday morning, responding to the Ukrainian forces' unilateral ceasefire.
The rebel announcement was made in Donetsk by Alexander Borodai, a leader of the self-styled "Donetsk People's Republic" which is defying Kiev.
On Friday, Ukrainian President Petro Poroshenko announced a 15-point peace plan and declared a week-long truce.
Mr Borodai was speaking after attending preliminary peace talks in Donetsk.
The high-level talks also involved representatives of the other breakaway region - Luhansk - and Viktor Medvedchuk, an opponent of the Kiev authorities who is close to Russian President Vladimir Putin.
Russia's Ambassador Mikhail Zurabov was also there, along with former Ukrainian President Leonid Kuchma, who is seen as a mediator for President Poroshenko. European mediators from the OSCE security organisation also participated.