BIN JAWWAD, Libya – Forces loyal to Moammar Gadhafi, some in helicopter gunships, pounded opposition fighters with artillery, rockets and gunfire Sunday, dramatically escalating their counteroffensive to halt the rebels' rapid advance toward the capital.
They also battled to loosen the grip of rebels on two cities close to Tripoli. But in at least one case, their tactics appeared to lead them into a trap.
Residents said pro-Gadhafi troops punched into the city of Misrata, 120 miles (200 kilometers) east of Tripoli, the capital, with mortars and tanks but were pushed out five hours later by rebel forces.
The rebel commanders intentionally opened the way for government tanks to enter the city, then surrounded them and attacked with anti-aircraft guns and mortars, said Abdel Fatah al-Misrati, one of the rebels.
"Our spirits are high," al-Misrati said. "The regime is struggling and what is happening is a desperate attempt to survive and crush the opposition. But the rebels are in control of the city."
As fighting across Libya grew more fierce, the international community appeared to be struggling to put military muscle behind its demands for Gadhafi to give up power.
A small British delegation sent to talk to the rebels headquartered in the main eastern city of Benghazi, meanwhile, was arrested by the rebels themselves, who said the group had entered the country without permission.
The rebels have set up an interim governing council that is urging international airstrikes on Gadhafi's strongholds and forces, though they strongly oppose foreign intervention on the ground.
Sunday's fighting appeared to signal the start of a new phase in the conflict, with Gadhafi's regime unleashing its air power on the rebel force trying to oust the ruler of 41 years.
Resorting to heavy use of air attacks signaled the regime's concern that it needed to check the advance of the rebel force toward the city of Sirte — Gadhafi's hometown and stronghold.