The Kremlin says that the presidents of Russia and Ukraine, Vladimir Putin and Petro Poroshenko, have discussed possible measures to restore peace to eastern Ukraine.
The Kremlin said in a statement that the two leaders had also expressed readiness to meet on the sidelines of an Asia-Europe summit in Milan on October 16-17 and discuss issues including natural gas.
State-controlled Russian exporter Gazprom cut gas supplies meant for internal consumption in Ukraine in June after Kyiv failed to pay its gas debts following acrimonious disputes and politically charged Russian price hikes.
The gas disputes and the conflict between Ukrainian forces and pro-Russian rebels in eastern Ukraine have caused concern about supplies to the European Union, which gets one-third of the gas it needs from Russia.
About half of that is pumped across Ukraine.
The Kremlin statement gave no details about the telephone talks.
A previous Putin-Poroshenko phone call preceded a September 5 cease-fire agreement between Kyiv and the separatists that has raised hopes for peace despite near-daily violations and the death of more than 330 people in eastern Ukraine during the truce.
Ukraine and NATO accuse Russia of sending troops and weapons into eastern Ukraine to support the rebels during the conflict, which has killed more than 3,660 people and driven Moscow's ties with the West to post-Cold War lows.
Analysts say Russia supported the cease-fire because it followed after rebel gains that left the separatists in control over large portions of Ukraine's Donetsk and Luhansk regions, giving Moscow a platform to influence Ukraine and keep it destabilized -- and out of NATO -- for years to come.
In an interview posted on the Russian tabloid "Komsomolskaya Pravda's" website on October 15, Putin's chief of staff repeated the Kremlin's denials of involvement in the conflict in eastern Ukraine, saying Russia provides only moral support to government opponents in eastern Ukraine.
Sergei Ivanov said it was up to Kyiv to ensure there is no "resumption of war" but that Russia could be a "guarantor" of a final peace deal.
"If final agreements are reached, Russia could be a guarantor in some form. There is such a practice in international affairs," Ivanov said.
Russian Prime Minister Dmitry Medvedev meanwhile told a U.S. television channel that a new "reset" in U.S.-Russian relations is "absolutely impossible" while sanctions against his country are in effect.
"Of course not. It is absolutely impossible," Medvedev said when asked during an interview with CNBC whether a reset was possible with U.S. sanctions in place.
In a transcript posted on the Russian government website on October 15, Medvedev said the U.S. sanctions were "destructive."
The United States has imposed several rounds of sanctions to punish Russia for its annexation of Crimea in March and its role in the conflict in eastern Ukraine.