NEW: The Taliban says it is not responsible for the attack
The U.S. suffered its largest loss of life in a single day in the province
A roadside bomb exploded under a bus in eastern Afghanistan on Monday, killing nine people and wounding 22 others, the Afghan interior ministry said.
The explosion took place in Wardak province, with the ministry blaming the Taliban for planting the bomb.
The Taliban said it was not responsible for the attack.
Americans, Afghan civilians killed in weekend violence
Wardak is known as the province where the United States suffered its largest loss of life in a single day in the war in Afghanistan.
In August 2011, the Taliban shot down a Chinook helicopter killing 38 on board, including 22 Navy SEALs and other members of U.S. special operations forces.
In February, Afghan President Hamid Karzai in February accused U.S. forces of “torture” and “murder” in the province.
The next month, Western powers pulled out of one of its districts after reaching an agreement with Karzai on the area’s future.