Officials say a roadside bomb has killed seven Afghan soldiers in the west of the country.

The spokesman for Afghanistan's defense ministry, Gen. Mohammad Zahir Azimi, said the powerful blast hit the soldiers' vehicle Sunday in the Dilaram district of Farah province.

Azimi said no other soldiers were seriously wounded, but declined to provide further details on the explosion.

There was no immediate claim of responsibility.

The Taliban have escalated attacks in recent months as they try to take advantage of the withdrawal of foreign troops, who handed over security for the country to Afghan forces over the summer.