The Taliban claimed responsibility for Tuesday's midmorning blast at an international coalition base in Logar province, southeast of Kabul, the capital.
The violence represents the latest militant attacks as international troops work to hand over more security to Afghan soldiers and police in preparation for the withdrawal of most of NATO's military presence in less than 18 months.
A suicide attacker drove the explosives-laden pickup truck into a gate at the NATO base near Logar's capital of Pul-i-Alam, provincial police chief Ghulam Sakhi Roogh Lawanay said.
At least 11 Afghan civilians were wounded, but no deaths were reported in the attack, he said. There was no confirmation of any casualties among international troops, and NATO's press office did not immediately respond to questions.
The truck belonged to a local contractor who was authorized to work on the base, and the explosives were hidden under a load of gravel, Lawanay said. He added that the truck was able to enter an outer gate of the base before the driver slammed the vehicle into a second gate.
Taliban spokesman Zabiullah Mujahid said in a statement that insurgents had launched the assault, which he claimed killed several foreign troops. The casualties could not be verified, and the Taliban often exaggerate the success of their attacks.
Earlier in the morning, a remote-controlled roadside bomb struck a bus just travelling northwest of Kabul, killing at least nine passengers, police said. The militant who set off the device was spotted running away from the scene and was captured by local villagers.
The bomb was placed under a bridge and was detonated when the bus drove over the span, said Mohammad Zahir, the criminal director for Kabul police. Broken glass and abandoned shoes of victims littered the road near the bus, which was flipped onto its side at the site of the explosion in Paghman district of Kabul province.
At least three other people were wounded in the blast, which went off at around 7 a.m. as Afghans were making their way to work.
"The person who pushed the button on the remote-controlled bomb was captured by villagers who saw him running," said Abdul Razaq, an Afghan police official in the Kabul area.
Initial reports said the bus was ferrying government employees to an Afghan ministry, but those reports could not be confirmed. Police speculated that the bomber might have tried to target a bus full of government workers but blew up a civilian bus by mistake.
Paghman district police chief Col. Amrullah said the explosion killed nine people, including two who were rushed to a local hospital but died within hours. He said three others were wounded. No one immediately claimed responsibility for the attack, but Amrullah blamed insurgents affiliated with the Taliban.
"It was planted by the enemy of the country," Amrullah, who like many Afghans uses only one name, said of the bomb. He said that police had seized the bomb's remote control from the man who was captured.
Roadside bombs are one of the Taliban insurgency's favorite weapons to target Afghan government forces and foreign troops, and they are a leading killer of ordinary Afghans.
Last year was the deadliest on record for civilians in the 10-year-old Afghan war, with 3,021 killed as insurgents stepped up attacks, according to the United Nations.
Also Tuesday, the NATO-led international military coalition said that one of its service members had died after an insurgent attack in eastern Afghanistan in the early morning. It gave no further details. NATO policy is not to identify the dead until family members have been notified.