Officials say a roadside bomb has exploded near a vehicle carrying paramilitary rangers in southern Pakistan, killing a security official and wounding three officers and five civilians.

Maj. Gen. Bilal Akbar, the director-general of the rangers, told reporters Saturday that a search operation has been launched in the city of Larkana where the attack took place.

Hours after the attack, Ahsanullah Ahsan, a spokesman for the Jamaat-ul-Ahrar militant group, claimed responsibility.

In a statement, he warned more such attacks in the future.

Larkana is a main city in Sindh province where Pakistani militants often target police and paramilitary rangers in response to an operation which was launched years ago to eliminate militants and criminal gangs. Pakistan has said this operation will continue until peace is fully restored there.