DONETSK, Ukraine — Pro-Russian separatists declared a cease-fire Monday in a surprise move that they said they hoped would lead to a settlement of the conflict in eastern Ukraine.

The announcement came as rebel leaders met with representatives of the Ukrainian government in Kiev, including the former president, Leonid D. Kuchma, as well as the Russian ambassador to Ukraine and a representative of the acting chairman of the Organization for Security and Cooperation in Europe.

“In answer to the cease-fire by Kiev, we commit to a cease-fire from our side,” said Aleksandr Borodai, the prime minister of the self-declared Donetsk People’s Republic.

Mr. Borodai, a Russian citizen, said the cease-fire would last until Friday, matching the timeline of the cease-fire announced last week by the new Ukraine president, Petro O. Poroshenko.