Islamabad: Four persons were killed on Tuesday when a vehicle was targeted with a roadside bomb in a region in northwest Pakistan bordering Afghanistan, police said.

The remote-controlled bomb went off as the vehicle passed through Ghawara Banda village in Lower Dir district of Khyber-Pakhtunkhwa province this morning.

Police said the bomb attack could be retaliation for a clash that occurred in the same area between Taliban fighters and a pro-government militia.

Two militants were killed in the clash.

The Dir region has witnessed several cross-border attacks by Pakistani Taliban fighters based in Afghanistan.

At least 20 people were killed in a suicide attack on the funeral of a tribal elder last month.

Lower Dir district borders the Swat valley, from where the Pakistan Army ousted Taliban fighters in 2009.

The Taliban chased out of Swat and Dir have set up bases in Afghanistan.