KABUL, Afghanistan — Militants in Afghan mountains where a Navy SEAL team was ambushed and a special forces helicopter shot down have fled into neighboring Pakistan and regrouped, a provincial governor said Thursday.

However, U.S. military spokesman Col. James Yonts said while "some of the enemy may have been able to escape" into Pakistan, many rebels remained in the mountains, surrounded by U.S. and Afghan forces.

U.S. forces lost three Navy SEALs in an ambush and another 16 troops when their chopper was downed on June 28 in Kunar province. Since then, about 300 U.S. troops backed up by attack aircraft and Afghan forces, have been hunting militants in the area.

But the Kunar province governor, Asadullah Wafa, said there had been little fighting in the area for several days.

"It's been peaceful because the militants escaped across the border to Pakistan and are now sheltering about 10 kilometers (six miles) on the other side," he told The Associated Press. "They may launch quick guerrilla raids across the border and then run back into Pakistan."

The governor declined to say how many militants are thought to be in the area.

The frontier snakes its way through mountains, and parts are unguarded. Rebels favor the area because of the ease of slipping across the border unnoticed and because the wooded, rugged terrain provides plenty of places ot hide.

The region has long been a haven for fighters loyal to renegade former premier Gulbuddin Hekmatyar, who is wanted by the United States. U.S. officials said al-Qaida fighters also were in the region. Osama bin Laden was not said to be there -- though he is believed to be somewhere along the Afghanistan-Pakistan frontier.

Yonts declined to comment on the number of rebels killed or captured, but said, "We feel very confident the operation has been very successful."

"We have denied them sanctuary. There have been no more IEDs (improvised explosive devices), no more abuse of Afghans in that area," he said. "We still have a large force up there that is conducting the mission to deny sanctuary and defeat the terrorists that are there."

The fighting in Kunar comes amid an unprecedented spate of bloodshed that has left more than 700 people dead in three months and threatened to sabotage three years of progress toward peace in Afghanistan. U.S. and Afghan officials have warned that the violence is likely to worsen in the lead-up to legislative elections set for September.