At least 50 people were killed in the airstrikes, which targeted various militant groups across Syria, including ISIS and the Nusra Front.
Last Tuesday, Kiev passed a law offering special status to regions controlled by pro-Russia rebels, in an effort to end the months-long violence.
Two countries with the rockiest relationships are considering collaborating with the international community to fight the Islamic State group.
Russia is denying reports that Exxon is pulling out of a massive drilling operation there in the face of sanctions.
Journalists were investigating reports that Russian soldiers had died fighting in Ukraine. Russia denies that its forces are operating there.
“There is no contract sanctity,” a U.S. official said. Accordingly, companies will have 14 days to wind down activities.
Arseniy Yatsenyuk made the comment after Europe decided to implement new sanctions against Russia over Ukraine.
Despite denials that Russian troops are in Ukraine, families with children in the Russian military are coping with 'mysterious' deaths.
You can't get to the French Riviera if your private jet won't take off.
The European Union has held out an olive branch, however, by saying it could lift some or even all of the sanctions within weeks.
Russia is looking to strengthen relations, as well as find new customers for its natural resources, in Asia, as relations sour with the West.
Warsaw said the volume of gas from Russia dropped by 45 percent, though Russia's Gazprom denied it had cut supplies.
The Bulava missile was fired from a Russian submarine near Finland and it hit a target near Japan.
Moscow denies sending troops into eastern Ukraine to support pro-Russian rebels battling Ukrainian forces.
Many residents of the Black Sea port are staying put, despite signs that it may soon be the next front in the Ukrainian conflict.
EU had earlier said that new sanctions, targeting Russia's defense and oil companies, could be announced if the cease-fire fell through.
"In some ways, we are solving a non-existent problem because we can't solve the existing ones," a Western defense official, speaking on condition of anonymity, said as the 28-nation summit ended on Friday.
Witnesses saw plumes of black smoke filling the sky on Sunday morning, in a further test for a cease-fire that is barely 40 hours old.
The Ukrainian military and the Kiev authorities have denied the claims, saying that there has been no fighting in the region.
NATO sought to reaffirm its relevancy in a post-Cold War at its Wales summit.
Pro-Russian separatists in Ukraine said on Friday a cease-fire agreement with Ukraine had been reached. The stand-down starts immediately.
Negotiators for Ukraine and pro-Russian rebels are near a cease-fire in Minsk, Belarus, but not much has changed.