Islamabad, Feb 28 (IANS): At least 18 people were killed Tuesday when gunmen hiding along the roadside, sprang out and peppered a passenger bus with bullets in Pakistan's Khyber Pakhtunkhwa province, a media report said.

The bus, carrying 25 passengers from Gilgit to Rawalpindi, was attacked in Kohistan district, reported Geo News.

The motive was unclear as Islamist militants are not active in the area, police said.

"Armed men hiding on both sides of the road attacked the bus. Initial reports said 18 people have died and seven were wounded," police official Mohammad Ilyas was quoted as saying.

The attack comes close on the heels of a terror attack in Peshawar Friday in which three policemen were killed and six others injured when three heavily armed suicide attackers went on a shooting spree and hurled grenades at a police station.

The brazen attack was carried out a day after a deadly car bomb killed over a dozen people and injured more than 20 in Peshawar.