Russia, Georgia Clash Over Breakaway Province

MOSCOW -- Russia and U.S. ally Georgia were on the brink of war Friday after Moscow sent troops and tanks into Georgia's breakaway province of South Ossetia, in a dangerous escalation of a long-simmering conflict in the strategically important Caucasus.

Sandwiched between Russia and Georgia, South Ossetia has a population of just 70,000. The pro-Russian region first sought to break from Georgia in the early 1990s in the tumult that followed the dissolution of the Soviet Union.

Russia said it was responding to a major attack by Georgian troops on the largely Russian enclave the previous night. Georgia said its ...