At least four police officers were killed and one was wounded when an explosive device blew up as their vehicle ran over it in the southern Afghanistan province of Kandahar, officials said Saturday.

The explosion occurred Friday in the Panjwai district, provincial police spokesman Ahmad Zia Durani said, according to local television channel Tolo.

The wounded agent was taken to a nearby hospital, the same source said.

Improvised explosive devices, or IEDs, and suicide bombings are the methods most frequently used by the Taliban against Afghan and international forces, though in practice they take a significant toll of civilian lives.

No armed group has yet claimed responsibility for Friday's fatal IED, though it was typical of the kind of aggression employed by the Taliban insurgency.

The Afghan conflict has entered one of its bloodiest moments since the U.S. invasion that led to the fall of the Taliban regime 12 years ago.

This year is the last that will see NATO troops in Afghanistan, according to the calendar for gradual withdrawal that will conclude next December, by which time local forces will be fully in charge of national security. EFE