Sri Lankan soldiers have pushed deep into the sole remaining Tamil rebel enclave and killed 43 guerrillas while nearly 82,000 civilians have fled the northern war zone within the last 72 hours, the military said Wednesday. Troops in recent months have ousted the rebels from all their former strongholds and hemmed them into what the government previously deemed a «no fire» zone to protect civilians. But troops entered the 7.7-square-mile (20-square-kilometer) zone this week to fight remaining rebels and free civilians trapped there, Associated Press reported. The military said it broke through a key rebel bunker in the coastal strip on Monday and that tens of thousands of civilians have been fleeing the area since then. By Wednesday, 81,423 civilians had escaped, the military said. Troops advanced deep into the zone and captured a part of during fighting with insurgents on Monday and Tuesday, killing at least 43 rebels, said Brig. Udaya Nanayakkara, the military spokesman. Tamil rebels are cornered into a stretch of about five miles (eight kilometers), he was quoted as saying by Associated Press.