Updated

American warplanes pounded a suspected Taliban (search) safe haven in the mountains of southern Afghanistan (search) during an assault that killed up to 76 insurgents and 12 security forces, officials said Wednesday. Five American soldiers were wounded.

The bodies of those killed in Tuesday's fighting littered a rugged Afghan mountainside. The surge in violence has raised fears that an Iraq-style quagmire is developing here, just months ahead of key legislative elections.

Two American CH-47 (search) helicopters were hit by small arms fire. One made an emergency landing and was repaired, while the other managed to fly back to a nearby base, U.S. military spokesman Lt. Col. Jerry O'Hara said.

He said 49 rebels had been killed, but Gen. Ayub Salangi, police chief for southern Kandahar province, said Afghan forces had recovered the bodies of 76 suspected insurgents from the battlefield on the border between Kandahar and Zabul (search) provinces.

He said the fighting spread to other areas Wednesday, and there were unconfirmed reports of more dead elsewhere.

Gen. Salim Khan, commander of about 400 Afghan policemen involved in the fighting, described the battlefield:

"Their camps were decimated. Bodies lay everywhere. Heavy machine guns and AK-47s were scattered alongside blankets, kettles and food," he said. "Some of the Taliban were also killed in caves where they were hiding, and U.S. helicopters came and pounded them."

Khan said hundreds of insurgents were in the mountains and his forces were locating them before giving the information to American officials on the ground, who called in air strikes. Many of the rebels have started to flee the area, he added.

O'Hara said AC-130 gunships, AH-64 Apache (search) helicopters, A-10 attack aircraft (search) and Harriers were "hammering enemy positions" and having a "devastating effect on their forces." Though the worst of the fighting had ended, U.S. and Afghan forces Wednesday were pushing forward with their hunt for insurgents, he said.

"We are not letting up on the enemy and will continue to pursue them until the fighting stops. Coalition and Afghan forces will continue to defeat these militants for as long as necessary to ensure the people of Afghanistan remain free of oppression and tyranny," he said.

O'Hara said the wounds of the five injured U.S. soldiers were not serious and they had been evacuated to a base in the southern city of Kandahar. Their names were withheld pending notification of their families.

Five Afghan police officers and seven soldiers were killed, while three officers and three troops were wounded, Khan said.

Some 30 militants were captured, including two district rebel commanders, Khan said. Eight of the 30 were wounded.

Meanwhile, a U.S. Air Force U-2 spy plane (search) crashed in an undisclosed location in southwest Asia while returning to its base from a mission in support of Operation Enduring Freedom in Afghanistan, U.S. Central Command said in a statement. The pilot was killed in the crash Tuesday night.

The death toll from this week's fighting appeared among the heaviest since U.S. planes pounded Taliban forces before the hard-line regime folded in late 2001. The last single battle of this magnitude was in August, when 70 suspected rebels were killed near the Pakistani border.

The new deaths bring to about 345 the number of suspected rebels killed since the start of a major upsurge in violence in March, when snows melted on mountain tracks used by the insurgents, according to U.S. and Afghan officials. In the same time, 29 U.S. troops, 38 Afghan police and soldiers, as well as 125 civilians have been killed.

The increase in fighting has reinforced concerns that the Afghan war is widening, rather than winding down. U.S. and Afghan officials warn things could get worse ahead of the parliamentary elections scheduled for September.

The officials have warned that foreign militants — backed by networks channeling them money and arms — had come into Afghanistan to try to subvert the polls. Fears have been further compounded by a spate of ambushes, execution-style killings and kidnappings reminiscent of the tactics of Iraqi militants.

Afghan officials claim the infiltration of rebels from neighboring Pakistan has contributed to the upsurge in violence and has called on Islamabad to crack down on militants there. On Sunday, Afghan intelligence agents scuttled a plot by three Pakistanis to assassinate Zalmay Khalilzad (search), the outgoing U.S. ambassador.