Soldiers carry a victim of a blast in Quetta, Pakistan. Picture: Naseer Ahmed/Reuters

Parachinar, Pakistan - An explosion ripped through a car on Tuesday killing six members of a family driving to a Pakistan village to attend a funeral in the northwestern district of Kurram near the Afghanistan border, officials said.

It was unclear whether the blast was a landmine or a roadside bomb planted by Islamist militants, said local government official Akbar Iftikhar. Both the militants and the Pakistani military use landmines.

"Three women and three men died on the spot," he said.

One survivor was in a stable condition, said Doctor Mumtaz Hussain at a hospital in Parachinar, the main town in Kurram.

Kurram is one of the seven districts along the Afghan border in the Federally Administered Tribal Areas (FATA), which have long been home to local and foreign Islamist militants.

Kurram is a predominantly minority Shi'a Muslim region that is often targeted by Sunni militant groups such as al Qaeda and the Islamic State. The six family members, however, belonged to Sunni sect, Iftikhar said.

The region has lately been the target of suspected US drone strikes, which mainly took out members of Haqqani militant network that is allied with Afghan Taliban and operates on both sides of the border.

The Haqqanis have been at the centre of the current tensions between the United States and Pakistan. Washington alleges that Islamabad supports the Haqqani militants, who attack the US and allied NATO troops in Afghanistan.