Kabul, Afghanistan ? U.S. troops and warplanes reinforced Afghan forces that were ambushed on a high mountain pass in a firefight that killed about 12 militants and wounded two American soldiers, officials said Tuesday.

In other reminders of Afghanistan’s instability, farmers fought a gunbattle with counternarcotics police in the south, and authorities said they arrested three men suspected of trying to abduct an American in the capital.

U.S. forces scrambled to the aid of a convoy of government troops who came under fire Monday from 30-35 militants on a mountain pass near Khost, 90 miles south of Kabul, American and Afghan officials said.

“The insurgents were reported to be fleeing the area but the coalition forces were able to locate them,” a U.S. military statement said. “Approximately a dozen insurgents were killed.”

Troops found a bomb rigged to one corpse, it said.

The two injured Americans were airlifted to the main U.S. base at Bagram for treatment and were listed in stable condition.

Police blamed Taliban rebels for the attack and suggested Afghan Gen. Khial Baz, a former senior military commander traveling in the convoy, was their target. None of the Afghans were reported hurt.

Khost is a former stronghold of Taliban and al-Qaida militants close to the Pakistani frontier and sees regular skirmishes between militants and Afghan and U.S. forces. It also is riven by violent factional and tribal disputes.

Baz, who survived several earlier attacks, commanded a provincial militia that worked closely with U.S. troops until it disbanded earlier this year under a disarmament program. He has survived several attacks.

Tuesday’s gunbattle broke out when protesters prevented members of a U.S.-trained unit from beginning a campaign to destroy opium poppy crops in southern Kandahar province, leaving one person dead and seven wounded.

Hundreds of protesters set fire to car tires and blocked a main road near Maywand, 50 miles from Kandahar city, deputy police chief Salim Khan told The Associated Press.

He said the operation was suspended, and officials were negotiating with the leaders of the protest.

President Hamid Karzai last year proclaimed a “holy war” on Afghanistan’s drug industry, which has become the world’s largest since U.S. forces ousted the hard-line Taliban government in 2001.

Meanwhile, an official said police in the capital have arrested three men suspected of trying to kidnap an American civilian two days earlier.

The men fit descriptions of the suspects in Sunday’s attack and appeared to be planning another abduction or robbery when they were apprehended, Interior Ministry spokesman Latfullah Mashal told the AP.

Three men forced the American into the trunk of their car after he had walked up a hill overlooking the city. The victim escaped by opening the trunk with a tire wrench and throwing himself from the vehicle as it sped toward Kabul airport.