A Taliban attack killed at least 21 people in northern Afghanistan, officials said Sunday, after a wave of lethal bombings in the capital as the insurgency escalates following a bitter power transition.

A Taliban attack killed at least 21 people in northern Afghanistan, officials said Sunday, after a wave of lethal bombings in the capital as the insurgency escalates following a bitter power transition.

The Afghan interior ministry said all those killed Saturday evening in the Khanabad district of Kunduz province were civilians, although local officials called them anti-Taliban militiamen.

The Taliban terrorist group claimed responsibility for the attack, which comes after a barrage of bombings in Kabul killed at least 51 people on Friday, the deadliest day for the capital in years.

"The incident took place (when) a suicide bomber detonated his suicide vest in Khanabad district," the interior ministry said, strongly condemning the "heinous act".

"The suicide attack... resulted in martyrdom of 21 civilians and wounding of 10 others."

But Abdul Wadood Wahidi, spokesman for the governor of Kunduz, said 22 militiamen -- including four of their commanders -- were killed by an improvised explosive device.

Kunduz is a volatile province where the Taliban recently came close to overrunning Kunduz city, in the most alarming threat to any provincial capital since the 2001 US-led invasion of Afghanistan.