KABUL A suicide bomber driving a truck of firewood attacked a NATO base in central Afghanistan, killing four civilians and injuring 77 U.S. troops on the eve of the 10th anniversary of the Sept 11 attacks, NATO and Afghan officials said on Sunday.
The Taliban claimed responsibility for Saturday's bombing, which created one of the highest injury tolls of the decade-long war and came just hours after the insurgent group slammed the United States for dragging Afghanistan into war.
An 8-year-old boy was among those killed in the bombing at a combat outpost in Wardak province, about 50 km (30 miles) south of the capital Kabul, the governor's office said in a statement. Fourteen civilians were also wounded.
None of the injuries to the U.S. troops was life-threatening, and the base remained operational although its perimeter fence was damaged, a spokesman for the NATO-led International Security Assistance Force (ISAF) said.
"Seventy-seven people is a large number, when you come to casualty figures, but the majority of them could very quickly be treated, there was nobody who was in danger of losing his life, and a high number of them returned to duty," said spokesman General Carsten Jacobson.
In a statement emailed to media, Taliban spokesman Zabihullah Mujahid said the truck used in the attack was packed with nine tonnes of explosives and more than 100 foreign troops were killed or wounded.
Doctor Muslim, the governor of Sayed Abad district, said the blast had also badly damaged the buildings that house the district government, and his cook was among the dead.
"A big cloud of smoke rose to the sky and foreign troops' helicopters were landing and taking off in the base for more than five hours after the blast," said Abdul Karim, a shopkeeper from the town near the base.
The windows and doors of more than 100 shops and houses were damaged in the explosion, the governor's office said.
Last month, militants shot down a helicopter in Wardak province, killing 30 U.S. troops, most of them elite Navy SEALs, in the deadliest attack on U.S. troops since the war began ten years ago.
Violence has escalated across the country, turning even some areas near the capital, such as Wardak, into insurgent strongholds and bringing insecurity to parts of the north and west that had been peaceful for years.
Foreign military casualties hit record levels last year -- and 2011 has been almost as bloody -- although civilians bear the brunt of the violence.
Eleven died this weekend. A roadside bomb in northern Kunduz province killed five civilians on Sunday, including three children. On Saturday another bomb in eastern Paktika province killed six civilians including two women.
The majority of civilian deaths are now caused by insurgents.
But the Taliban in a statement issued hours before the truck bombing blamed the United States for causing bloodshed in Afghanistan.
"Each year, the 9/11 reminds the Afghans of an event in which they had no role whatsoever, but, using this as a pretext and a clout, the American colonialism shed blood of tens of thousands of miserable and innocent Afghans," Mujahid said.
Afghans have an "endless stamina for a long war," he warned and asked foreign nations to press the United States to stop attacking the country.
NATO-led forces have committed to withdrawing all combat troops by the end of 2014, and in July began the first phase of a gradual process to hand security control to Afghan troops.
But U.S. Ambassador Ryan Crocker at a ceremony to mark the anniversary of the attacks in New York and Washington said the United States will remain engaged in Afghanistan.
"We are and will remain committed to Afghanistan and the region. We are in this for the long haul. We are transitioning security responsibility to Afghan forces, but transition does not mean disengagement," Crocker said.
(Additional reporting by Hamid Shalizi in Kabul and Obaid Ormur in Logar province, writing by Sanjeev Miglani; Editing by David Cowell)