The Ukraine crisis is expected to be the focus of meetings between Russian President Vladimir Putin and European leaders this week.
An October 16-17 Europe-Asia summit in Milan is the first chance for Putin and European leaders to discuss Ukraine face-to-face since D-Day anniversary ceremonies in France in June.
Kremlin foreign-policy aide Yury Ushakov said Putin will meet on October 16 with German Chancellor Angela Merkel and attend a dinner involving other leaders.
Ushakov said the "accent" would be on Ukraine at an October 17 breakfast meeting that the leaders of Germany, France, Britain, Italy, and the European Union are expected to attend, along with Ukrainian President Petro Poroshenko.
A bilateral Putin-Poroshenko meeting is also possible, as is a four-way meeting with Poroshenko, Merkel, and French President Francois Hollande.
The White House said U.S. President Barack Obama would discuss the Ukraine crisis, among other pressing issues, in a video conference with Cameron, Hollande, Merkel, and the Italian leader later in the day.
The Kremlin said earlier on October 15 that Putin and Poroshenko had discussed possible measures to restore peace to eastern Ukraine during a telephone call.
A brief Kremlin statement said the two leaders had also expressed readiness to meet on the sidelines of the Milan summit 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.
'No Sign Of Russian Pullback'
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.
In the eastern region of Luhansk on October 15, the Ukrainian military said fighting took place "at Bakhmutka" on a road where pro-government forces have several checkpoints.
The region’s pro-Kyiv governor, Hennadiy Moskal, said rebel fighters surrounded more than 100 troops, but military spokesman Andriy Lysenko denied that. Moskal also said several injured soldiers were captured.
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.
NATO's top military commander said on October 15 that the alliance had not seen "major movement" so far of Russian troops from a region bordering eastern Ukraine.
U.S. Air Force General Philip Breedlove, the supreme allied commander Europe, was speaking to AP news agency, days after Russian President Vladimir Putin ordered about 17,600 Russian troops to return to their bases after what Moscow described as training drills in the Rostov region.
NATO has refuted previous Russian claims of troop withdrawals from the regions bordering Ukraine.
Russian Prime Minister Dmitry Medvedev said in remarks published on October 15 that a new "reset" in Russian-U.S. ties was "absolutely impossible" as long as sanctions the United States has imposed on Moscow over its role in the Ukraine crisis remain in place.
Medvedev said Putin's recent order to move troops that have been deployed near Russia's border with the conflict zone in eastern Ukraine was a purely domestic matter and should not be interpreted as a signal to Washington.
Analysts say Russia supported the Ukraine 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.
With reporting by Reuters, AP, TASS, Interfax, and RIA Novosti