U.S. soldiers and warplanes drove off an insurgent attack on a new American base early Wednesday, killing 19 militants in an area where rebels are trying to resist a push by coalition troops into remote mountains of eastern Afghanistan.

In the volatile south of the country, wracked by the bloodiest fighting in nearly five years, suspected Taliban rebels hanged a 70-year-old woman and her son from a tree, accusing them of spying for President Hamid Karzai's government, officials said.

Meanwhile, Karzai, whose popularity has declined because of slow progress in reconstructing the war-battered country and poor security, signaled in an interview that he won't run for president again in elections slated for 2009.

CountryWatch: Afghanistan

In the capital, a soldier in the NATO-led coalition providing security to much of the country died in a vehicle accident on Wednesday, NATO said without offering more details. Elsewhere, a NATO soldier in the Musa Qala district of Helmand province, where the British have a base, was seriously wounded, the alliance said.

The raid on the U.S. base at Kamdesh in the eastern province of Nuristan — one of the country's wildest regions — was staged by extremists likely belonging to the Hezb-e-Islami militant group, who attacked from three directions out of forests using rocket-propelled grenades and small-arms fire, the U.S. military said.

Several hundred soldiers at the base, which lies in a small town but backs onto a sheer mountain face, returned fire with mortars and small arms before jets dropped four 500-pound bombs, ending the clash that lasted more than two hours.

"This is the first large, coordinated attack on our base since we arrived three weeks ago," said Lt. Joel Rees, 26, of Memphis, Tennessee. "When light broke, we found large crater holes from the RPG attack throughout the base and several tents had bullet holes."

Maj. Tom Sutton, of the 3rd Battalion, 71st Infantry Regiment of the 10th Mountain Division, based in Fort Drum, New York, said at least 19 militants were killed in the battle, the most ferocious he said he had witnessed in the area. A coalition statement said two American soldiers were wounded, but returned to duty after treatment.

Sutton, 35, from Spokane, Washington, spoke to The Associated Press at the main U.S. base in the area, at Naray, about 40 kilometers (25 miles) to the south in Kunar province, close to the border with Pakistan. Kamdesh can only be reached by helicopter.

The region is a stronghold of Gulbuddin Hekmatyar, a renegade Afghan warlord whose Hezb-e-Islami faction has ties with Osama bin Laden and now fights Karzai's government. His fighters are also supported by loyalists of the Taliban regime, which was driven from power in late 2001 by U.S.-led forces for harboring the al-Qaida leader.

With NATO recently taking charge of security in Afghanistan's south, U.S. troops are increasingly focusing on extending the Karzai government's writ in the still-dangerous east along the frontier with Pakistan and hunting for fugitives like bin Laden.

"It was a very severe attack that indicated that U.S. forces are entering areas where militants had long gone without being attacked," Capt. Charles Schwab, 30, of Tionesta, Pennsylvania, said of the assault in Kamdesh. "It shows we are making an impact and forcing the enemy to fight to the death."

In the south, local officials said a 70-year-old woman and her 30-year-old son were killed by Taliban fighters Monday in the village of Daigh, near the town of Musa Qala in Helmand province — hanged from a tree for allegedly spying for the government.

Karzai condemned the slaying, calling it an act "against historical and cultural values of Muslims."

Months of violence in the south, the heartland of the hardline Taliban religious militia, have chipped away at the president's credibility, exposing the weak grip he has over a region also mired in the booming trade in opium and heroin.

In an interview with Fortune magazine published this week, Karzai gave a strong hint he would not run again for president in the next elections, slated for 2009.

"I don't think it is good to be running all the time. Let other people get a chance to run," he was quoted as saying.

His spokesman, Khaleeq Ahmed, said Wednesday that the article properly characterized the president's views.

Karzai was named Afghanistan's transitional leader soon after the Taliban's ouster, then became its first democratically elected president in late 2004, with a five-year term.

He claimed success in building the country's economy, but conceded corruption is rife, saying that "lots of people" in his administration profited from the drug trade and that he had underestimated the task of eradicating the cultivation of opium poppies.