KABUL, Afghanistan -- A roadside bomb detonated under a bus in Afghanistan on Monday, killing nine civilians, officials said. It was the latest in a string of attacks over the past week that have left noncombatants dead.
The bus was driving from the southern province of Ghazni to Kabul when the blast ripped it apart about 8:30 a.m. in the Sayedabad district of troubled Wardak province, said Attaullah Khogyani, spokesman for the provincial governor. The attack also injured 21 people, including six women and four children.
"It's the Taliban's fault," Khogyani said. "They're planting roadside bombs to target people, create fear across the nation and show up the weakness of government."
However, Taliban officials denied responsibility in statements to the media.
In another development, Interior Ministry spokesperson Sediq Sediqqi said French freelance reporter Pierre Borghi, 30, who was kidnapped from downtown Kabul nearly four months ago, had been released. Sediqqi declined to provide further details.
A French charity worker was later kidnapped in the same area as Borghi but was subsequently freed.
It was not immediately clear whether Borghi was seized by the Taliban, other insurgents or criminal gangs. An Afghan official who requested anonymity said he had escaped his captors in Wardak, which is just outside of the Afghan capital.
Though kidnapping in Afghanistan is sometimes motivated by politics or ideology, it's also frequently done for profit, particularly when rich Afghans are the targets. In other cases, it is a combination of the two motives, with criminal gangs grabbing a victim before selling him or her to militant groups.
Monday's bus bombing was the latest in a string of attacks over the past week.
On Saturday, at least 10 children and a woman were killed during a NATO attack on militants in eastern Kunar province, according to Afghan officials, after an attack that killed a U.S. advisor and wounded four Afghan troops. NATO confirmed the airstrike but said it was still investigating whether any civilians were killed.
Civilian deaths from NATO airstrikes and ground fighting have been a major source of tension between Afghanistan and the U.S.-led coalition. Afghan President Hamid Karzai condemned Saturday's reported deaths and ordered an investigation.
Also on Saturday, a car bomb in Zabul province killed three U.S. soldiers, a Defense Department contractor and Anne Smedinghoff, a 25-year-old diplomat in the U.S. Embassy in Kabul. Secretary of State John F. Kerry paid tribute to Smedinghoff, who joined the Foreign Service after graduating in 2009 from Johns Hopkins University with a degree in international relations.
The violence made Saturday the deadliest day for U.S. personnel in Afghanistan in eight months.
And in one of the worst attacks in recent years, Taliban fighters using a car bomb, suicide vests, automatic rifles and grenades raided a provincial court compound last week in western Farah province, killing 44 people, most of them civilians.
The violence comes as NATO forces are handing over more security responsibility to Afghan troops and police in advance of the coalition's planned withdrawal of combat troops by late 2014. Illiteracy, poor morale, desertions, weak intelligence and limited air power have eroded the Afghan military's effort to take over.
Special correspondent Hashmet Baktash contributed to this report.