A minibus carrying workers to a US base blew up in the southern Afghan city of Kandahar on Thursday, killing 10 people and wounding 15 others in an incident suspected to be caused by the detonation of explosives planted on the vehicle.

The blast happened during two key developments in Afghanistan: an upsurge in attacks throughout Afghanistan by Taliban fighters, and the recent start of a major combat operation aimed at a resurgent rebel force.

Called Operation Mountain Thrust, more than 10,000 U.S., Afghan, and coalition forces have fanned out across Kandahar and neighboring Oruzgan, Helmand, and Zabul provinces to conduct sweep operations against safe havens.

Working with Afghan forces they expect to spend several days rooting out Taliban safe havens. The coalition forces include Canadian and British troops.

Sher Shah, a Kandahar police official, said Thursday's accident -- which took place at 7:40 a.m. -- occurred after a Toyota Coaster mini-bus blew up after a collision between the bus and a car.

"The Coaster was carrying some laborers and also some translators to the American base in Kandahar," he said.

"We think that the explosives were hidden in the bus and perhaps they were originally supposed to blow up later when the vehicle reached the base. The bus is much more damaged than the car. Some of those injured were passers by."

Kandahar's main hospital has received seven dead bodies and treated 17 injured people, a doctor there told CNN.

A spokesman for the Taliban claimed responsibility for the attack, according to the Reuters news agency.

"It is our success. It shows that we have access to even highly-guarded government places and we can do whatever we want," Mullah Hayat Khan, told Reuters.

Coalition officials says have said the level of violence in Afghanistan's southern region have been on the rise, coinciding with a transition from U.S.-led to NATO-led operations.