A suicide bomber detonated explosives at the gate of a U.S.-run military base in eastern Afghanistan on Thursday, killing two Afghan security guards.
To the west, a roadside bomb killed at least 20 passengers traveling on a minibus in Herat province, another example of civilians being caught in the crossfire of the fighting between Taliban insurgents and the U.S.-led coalition.
The attack at the American base occurred at 6:45 a.m. local time (10:15 p.m. ET Wednesday). The AFP news agency reported that the incident occurred at the heavily fortified provincial reconstruction team base that Americans operate near Gardez, the capital of Paktia province.
The International Joint Commission in Afghanistan confirmed the attack and told NBC News that two Afghan guards were killed.
Army Master Sgt. Nicholas Conner, a spokesman for the U.S.-led coalition, said there were no NATO causalities.
The Taliban claimed responsibility for the bombing.
"A suicide bomber tried to attack the base with a truck bomb but he was encountered at the first gate by Afghan guards. He set off his bombs there," Paktia provincial police chief Abdul Ghadar Sapai told AFP.
Abdul Ihay Atrafi, an Afghan Border Police commander for several provinces in southeast Afghanistan, said the bomber hid the explosives in a truck loaded with wood. The bomber sped through an outer gate, then blew up the vehicle when he came under fire at a second gate, Atrafi said.
He said several people also were wounded in the explosion.
"It was a very powerful explosion because it was a truck," Atrafi said, adding that the blast caused extensive damage and shattered windows nearby.
In a statement emailed to the media, Taliban spokesman Zabiullah Mujahid said the attack was carried out by a 70-year-old suicide bomber from Nuristan province in eastern Afghanistan along the Pakistan border. He said the truck contained 7 tons of explosives and that the explosion killed and wounded more than 60 U.S. soldiers.
The Taliban often exaggerate casualties and other details of their attacks.
There are more than 20 so-called PRTs across Afghanistan where international civilian and military workers train Afghan government officials and help with local development projects.
Deadly minibus bomb
Meanwhile, the minibus ran over a roadside bomb in Obe district in the western Herat province, setting off a blast that killed at least 20 of the 25 passengers, said Raouf Ahmadi, a police spokesman for several provinces in western Afghanistan.
Abdul Bashir, an elder of a village in the district, put the death toll at 23.
"It was a big, powerful blast," Bashir said. "Among the dead are men, women and children. The bodies are not easily recognizable."
Mohyuddin Noori, a spokesman for the province's governor, said the bus was on its way to a bazaar where the passengers were going to shop.
Noori also said that a small truck hit another roadside bomb Thursday morning in the same district, seriously wounding at least four civilians.