Jordan said on Saturday three people were killed during a police raid on a house sheltering militants suspected of being behind a bomb attack on a police van.
Security forces stormed a building in the city of Salt where suspects behind the planting of the home-made bomb that killed one policeman on Friday were believed to be hiding.
Government spokeswoman Jumana Ghunaimat told the state news agency Petra that three suspects had been arrested so far in an operation that was still underway against a cell hiding in a building in the center of Salt city, about 30 km (18 miles) west of Amman.
The suspects had refused to hand themselves over to the security forces and blown up part of the hilltop building, Ghunaimat added.
Police had earlier blamed a gas canister for Friday’s blast near the site of a music festival in the town of Fuheis.
Ambulances were seen rushing to the main city hospital from near the building in an residential area of Salt that was sealed off by police.
Radical Islamists have long targeted Jordan, a tightly policed country that is also a staunch regional ally of the United States and signed a peace treaty with Israel.
Several incidents over the past few years have jolted the Arab kingdom, which has been comparatively unscathed by the uprisings, civil wars and Islamist militancy that have swept the Middle East since 2011.