A time bomb exploded in a passenger van near the Pakistan-India border, killing five people and injuring 27 in what authorities said likely was a terrorist attack, officials said Thursday.

A police spokesman in Sailkot, 180 miles southeast of Islamabad, said a bomb connected to a timer was placed under a passenger seat in the van and was set to detonate about 20 minutes after the vehicle left Sailkot Wednesday night for the border town of Shakargarh.The bomb killed or injured all aboard the van, officials said.

"We know there is an organized group behind the recent explosions in the country but can't say which," the spokesman said.

Pakistan has suffered several bomb attacks since the war in the Persian Gulf began. Officials suspect Iraqi-supported terrorists were behind the attacks but are reluctant to say so because of a sudden increase in pro-Iraq sentiment among the population of the Muslim nation following allied bombing of Iraq.

Pakistan and Iraq historically have not had good relations as Baghdad has supported India on several issues, including disputed Kashmir territory.