Tens of thousands flee Chad violence; U.N. authorizes France, other nations to help government under rebel attack for third day.(Main)

Byline: TOM MALITI Associated Press

N'DJAMENA, CHAD - Chadian rebels renewed their assault on the capital of this oil-rich central African country Monday, and tens of thousands of people fled as gunfire crackled and artillery shells exploded across the city.

The third day of fighting in N'Djamena threatened to further destabilize an already violent swath of Africa that is home to hundreds of thousands of refugees and borders Sudan's war-ravaged Darfur region.

Hours after the rebels went back on the attack following an overnight retreat, the U.N. Security Council authorized France and other nations to help Chad's government.

France has …