Pro-Russian separatist leaders in eastern Ukraine say they've agreed to observe a temporary cease-fire until June 27, ending 10 weeks of fighting against Ukrainian forces.
Aleksandr Borodai, the self-styled prime minister of the self-declared "Donetsk People's Republic," made the announcement on June 23 after peace talks with representatives from Moscow, Kyiv, and the Organization for Security and Cooperation in Europe (OSCE).
The talks were chaired by former Ukrainian President Leonid Kuchma.
Borodai said separatists in the self-declared "Luhansk People's Republic" also agreed to a cease-fire until June 27.
He added that separatist officials would join more talks aimed at resolving Ukraine's crisis, which has pitted Ukrainian armed forces against pro-Russian separatist fighters.
The separatists previously rejected a unilateral weeklong truce declared on June 20 by Ukrainian President Petro Poroshenko.
The announcement seemed to affect the situation on the ground, with Ukrainian officials reporting an abrupt halt to insurgent attacks in eastern Ukraine.
Kuchma said that, if both sides observe the cease-fire, then "a normal peace process could start."
WATCH: Separatist leaders in eastern Ukraine said they agreed to observe a temporary cease-fire until June 27.
In Washington, U.S. President Barack Obama urged Russian President Vladimir Putin to support peace in Ukraine and said Moscow would face further "costs" if it did not take steps to reduce tensions in the country.
The White House said Obama made his comments to Putin via phone on June 23, calling on him to halt the flow of "arms and materiel across the border" and Kremlin support for "militants and separatists."
Obama added that Russia will face additional sanctions if Washington does not see "concrete actions to de-escalate the situation."
Putin, for his part, was said to have emphasized to Obama the importance of direct talks between Ukrainian officials and the pro-Russian separatists in eastern Ukraine.
Earlier on June 23, European Union foreign ministers repeated their threat of wider sanctions against Russia if it failed to support Poroshenko's peace plan.
The bloc has so far ordered visa bans and asset freezes for officials but refrained from imposing broader economic sanctions on Russia.
Ahead of an EU foreign ministers meeting in Luxembourg on June 23, British Foreign Secretary William Hague said the EU will be able to agree further measures at a summit of EU leaders on June 27, if necessary.
He said Moscow must be in "no doubt" it faces further sanctions.
Swedish Foreign Minister Carl Bildt accused Russia of "conducting a propaganda war with full speed," adding that Moscow must face further sanctions unless it changes course.
Meanwhile, the European Council said it has finalized technical preparations ahead of the signing of an Association Agreement with Kyiv in Brussels on June 27.