Petro Poroshenko's initiative meets a major demand put forward by Moscow and helps address growing concern among rights groups about Kiev's use of tanks and air power in heavily populated areas to suppress the pro-Russian insurgency.
But the 48-year-old chocolate baron and political veteran stopped short of accepting the Kremlin's request to allow Russian aid into the eastern rustbelt -- a move Kiev fears could be used to help arm the rebels.
Russia said the decision was "welcome" but left room for concern that Poroshenko might only step up his offensive once civilians leave for safer parts of Ukraine.
"Military operations are continuing and even intensifying in a number of cases," Foreign Minister Sergei Lavrov said after meeting his German and Ukrainian counterparts in Saint Petersburg.
But German Foreign Minister Frank-Walter Steinmeier said he saw "the light at the end of the tunnel" and a "readiness from all sides to act to de-escalate the crisis".
The peace push came after the first of what are meant to be nearly daily meetings with Moscow's ambassador to Kiev and a representative from the Organisation for Security and Cooperation in Europe.
The high-stakes negotiations include efforts to stave off a Russian gas cut that would also impact Europe and plunge his economically-devastated country into even deeper recession.
A marathon round of EU-mediated gas talks broke up in Brussels early today for consultations and another session is due to begin at 1900 GMT.
"We heard about this initiative but doubt it will come into force," Donetsk "deputy governor" Andriy Purgin told Russia's Interfax news agency.
