Russia's defense ministry has released footage of its soldiers arriving in Belarus for joint military exercises. It says the drills are aimed at "practicing coordinating allied forces." It comes amid heightened tensions over Russia's military build-up near the border with Ukraine. The West has warned about a possible Russian aggression against Ukraine but Moscow denies any plans for an attack. The U.S. and its allies have warned Russia of economic sanctions if it invades its neighbor. NATO also says the Western military alliance is watching closely as Russia moves troops and arms into Belarus for drills.