Gunmen opened fire on a school bus in Pakistan on Thursday, killing two girls and wounding five other children, police said.

The attack occurred in the town of Attock in the central province of Punjab when the children were travelling to attend classes in the morning, police official Usman Haider said.

Mr Haider said that dead and wounded children were aged between five and 10. 

He added that the motive of the crime was not immediately known, but the preliminary investigation pointed towards a feud between two families. 

“We are also looking into the possibility of terrorism,” the officer said.

Pakistani President Asif Ali Zardari condemned the incident and ordered police to capture the gunmen, his office said in a statement.

Islamist militants have attacked students at schools, colleges and universities in the past.

Taliban gunmen killed nearly 150 children in a gruesome attack at a military-run school in north-western Pakistan in 2014.

A Taliban member also fired at a school bus in Swat in 2012.

That attack wounded Malala Yousafzai, who went on to win the Nobel Peace Prize in 2014. 

(dpa/NAN)