KABUL: Bomb blasts and clashes killed five policemen, including a district chief, and eight other people in insurgency-hit Afghanistan Sunday, authorities said.

A bomb planted by Taliban killed the police chief of Sar Hawza district in southern Paktika province as he was travelling, a provincial government spokesman said.

"The convoy was moving from Urgun district to Sar Hawza district when a roadside bomb exploded," spokesman Hamidullah Jawak said.

A clash erupted after the blast and one Taliban was also killed, he said.

The administrative head of the district, which is near the border with Pakistan, was wounded in the attack.

Separately, in the same district, Taliban militants attacked security guards working for a private construction company and killed five of them, Jawak said.

Four more policemen were killed after their remote post was attacked by Taliban rebels riding motorbikes in the northwestern province of Faryab, provincial police chief Khalilullah Ziayee told AFP.

The Taliban also suffered casualties, the police chief said, but he had no details. In volatile Kandahar province, a mother and her son were killed when a motorbike they were riding was blown up by a roadside bomb, also on Sunday, the interior ministry said, blaming the attack on insurgents.

"Two civilians, a mother and a son, were killed when a mine... planted by the enemies of Afghanistan exploded under their motorbike," the statement said.

On Saturday, meanwhile, an army soldier was killed in a gun battle with Taliban which also left two rebels dead in the central province of Ghazni, a place which sees regular Taliban unrest, the provincial police chief said.

The Taliban, an Islamic militia in power between 1996 and 2001, is the main group behind an increasingly bloody insurgency that followed the hardliners' removal from government.

Insurgency-linked unrest has surged in recent weeks as thousands of extra international troops move in ahead of August 20 presidential and parliamentary elections which officials fear may be jeopardised by the violence.