Russian helicopters blasted their targets not far from where the U.S. and NATO allies have just begun fortifying their air defenses.
Two Syrian activist groups with ties to the country's opposition also offered opposing claims about the Islamic State militant group leader's death.
The U.S. and Russia have taken leading, often opposing, roles in world affairs, but recent events in Syria and North Korea may invite more cooperation.
The drill used four different kinds of warplanes in a joint assault.
Moscow has sent 2,500 troops to its western border region to practice landing in unfamiliar territory.
Russia dismissed jokes by U.K. Defense Secretary Michael Fallon and called the new HMS Queen Elizabeth "a large, convenient naval target."
The U.S. and Russian militaries have found themselves increasingly at odds in the world.
President Donald Trump has changed course a number of times on Syria, but recent events pit him directly against Russia and Iran.
Syria's President Bashar al-Assad made a series of public appearances, surrounding himself with military officials and supporters amid U.S. threats.
The Arctic is a priority zone for the Russian Navy's current expansion and modernization strategy.
Ronald Reagan and Mikhail Gorbachev signed the Intermediate-Range Nuclear Forces Treaty in 1987. Now Republican hawks want to scrap it.
The top U.S. Army commander in Europe complained that Russia is being too secretive about upcoming large-scale military drills.
Russian confidence in their army is high though. Over a third think their men and women in uniform are the best in the world.
A Russian fighter jet reportedly buzzed a U.S. reconnaissance plane near the Baltic Sea, hours after the U.S. shot down a drone in Syria.
Russia severed a military hotline with the U.S. and has said it will turn its air defenses on any U.S. plane that crosses battle lines in Syria.
The U.S. is finishing up naval exercises with NATO allies in the Baltic region, but Russia has an even bigger display of military might in the works.
Russia is one of the few countries to recognize South Ossetia as independent.
Russian Foreign Minister Sergei Lavrov told Secretary of State Rex Tillerson that the U.S. must stop attacking pro-Syrian government forces fighting ISIS.
September's large drill in the disputed South China Sea region will be one of an annual series.
Russian President Vladimir Putin criticized the media, claiming it has stayed "silent" on U.S. and NATO military expansion.
Russian lawmaker Vyacheslav Alekseyevich Nikonov said nuclear weapons would be necessary in the event of a U.S. or NATO invasion of Crimea or eastern Ukraine.
Russia's decision last year to deploy of the Iskander-M to a region bordering Poland and Lithuania prompted concern among both NATO allies.
The Latvian ambassador to Canada said he does not feel safe even as NATO forces arrive ahead of Russian war games simulating an attack on the West.