Following hours-long discussions on a peace initiative for Ukraine, the leaders of Russia, France and Germany announced Friday that Russian President Vladimir Putin and his Ukrainian counterpart Petro Poroshenko would discuss a peace plan in a four-way telephone call on Sunday.

The proposal to end the fighting in eastern Ukraine is expected to focus on reviving the Minsk ceasefire agreement, which was signed in the Belarusian capital in September last year. The agreement failed to halt the conflict in eastern Ukraine, where pro-Russian rebels eventually seized more ground, raising concerns for Kiev and its supporters, BBC reported.

The announcement about Sunday’s discussions came after German Chancellor Angela Merkel and French President Francois Hollande went to Moscow on Friday in an attempt to prevent further escalation of the conflict that has already killed more than 5,000 people in eastern Ukraine. Merkel and Hollande had met the Ukrainian president the previous day in Kiev.

“Work is currently under way on drafting the text of a possible joint document on the implementation of the Minsk agreement, which would include the proposals made by the president of Ukraine and President Putin,” Dmitry Peskov, a spokesperson for Putin, told the Associated Press (AP), adding that Sunday’s phone call will also involve Merkel and Hollande.

Meanwhile, observers in the U.S. have expressed their skepticism over the call. According to them, it is high time that the concerned authorities take concrete steps to stop the fighting instead of simply holding talks.

“I'm not going to say it's a positive sign that they're listening,” State Department spokesperson Marie Harf told AP. “They've been listening. They just haven't been acting.”

Meanwhile, the escalating conflict between Kiev force and rebels in eastern Ukraine is also likely to be discussed at a security conference in the German city of Munich on Friday. World leaders, including Merkel, U.S. Secretary of State John Kerry and Russian Foreign Minister Sergei Lavrov are expected to speak at the event, BBC reported.