Fifteen people have been killed after suicide bombers struck two government offices in southern and western Afghanistan as militants step up attacks across the country, authorities said.

At least 10 people were killed and more than 20 others injured in a suicide bomb attack outside a government office in western Afghanistan during rush-hour today, authorities said.

A suicide bomber in a four-wheel-drive vehicle detonated his cache of explosives in western Afghanistan today, killing nine people and wounding 21.

Militants attacked a police vehicle in western Afghanistan, killing four officers, an official said today.