More On Ukraine

Ukrainian troops began moving against separatists in eastern Ukraine as NATO considered shoring up defenses in Europe.

The top U.S. commander in Europe said the DoD must reconsider the drawdown of forces following Russia's provocative actions.

Russia has been engaging in "hybrid war" by using its forces covertly to bolster Russian-speaking proxies, Breedlove said.

The U.S. has deployed 12 A-10 Warthog planes from an air base in Germany to Romania as part of a theater-security effort to...

Mattis' trip comes as the United States is mulling giving Ukraine lethal weapons after Russia's annexation of Crimea.

Tensions over Ukraine have led to suggestions the Obama administration take a tougher defensive posture toward Russia.

NATO’s commander announced a modest shift of troops, planes and ships to eastern Europe during the Ukraine crisis.

The U.S. should send a message to Russia by stopping troop reductions in Europe, the NATO commander said Tuesday.

One of the last U.S. combat units in Europe is asking for bigger guns amid rising tensions over Russia's involvement in...

Defense Secretary Jim Mattis on Thursday pledged continued aid to Ukraine as it clashes with pro-separatist, Russian-backed...