KIEV, Ukraine — Russia and Ukraine said Wednesday they are working on a deal to halt months of fighting in eastern Ukraine, an announcement that threatened to upstage a crucial NATO summit on the crisis that has chilled East-West relations.

Western leaders expressed some skepticism over the plan, noting it wasn’t the first attempt to establish a truce, and that earlier efforts had failed.

Ukrainian President Petro Poroshenko’s office said after a telephone conversation with Russian President Vladimir Putin that the two leaders have agreed on steps for a cease-fire.

In a televised statement, Putin spelled out a seven-point plan for ending hostilities in eastern Ukraine, where Russian-backed separatists scored significant gains last week against government forces after four months of fighting.

Speaking on a visit to Mongolia, Putin said the rebels should halt their offensive and the Ukrainian government forces should pull back to a distance that would make it impossible for them to use artillery and rockets against residential areas. He also urged international monitoring of a cease-fire, a prisoners exchange and the delivery of humanitarian aid to war-ravaged regions.

Representatives of Russia, Ukraine, the rebels and the Organization for Security and Cooperation in Europe could finalize the peace deal as early as Friday, Putin said.

Poroshenko also voiced hope that Friday’s talks in the Belarusian capital of Minsk would allow both sides to “take real steps to achieve peace.”

He discussed the plan with German Chancellor Angela Merkel, saying it should include the OSCE monitoring of a cease-fire, the withdrawal of foreign troops, a buffer zone on the border and the release of all Ukrainian prisoners held in Russia, according to his office.