Jordan said Saturday that four people were killed during a police raid in a house where suspected fighters were hiding who had bombed a police car the day before.
Security forces stormed a building in Salt City where suspects behind the planting of the homemade bomb that had killed a police officer on Friday were suspected of hiding.
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 Government spokeswoman Jumana Ghunaimat told state news agency Petra that three suspects have been arrested in an operation following a cell in a building in the middle of the hill town of Salt, about 30 km away. west of Amman.
The suspects had refused to surrender to the security forces and blew up part of the hill, Ghunaimat added.
Later, Ghunaimat said the security forces wanted to take the place to see if civilians were held hostage there.
Witnesses heard several strong explosions near the site, which a security source reported that explosives were detonated by the police as they approached the militants.
The police had earlier blamed a gas tank for the explosion on Friday near the site of a music festival in the town of Fuheis.
Near the building in a residential district of Salt, which was cordoned off by the police, ambulances were brought to the city's main hospital.
Several incidents in recent years have shaken the Arab kingdom, which has survived comparatively unscathed by riots, civil wars and Islamist militancy that has conquered the Middle East since 2011.
Militants from al-Qaeda and other radical jihadist groups have long targeted the allied kingdom of the United States and dozens of militants are currently serving long prison sentences.
Jordan earlier this year said it had thwarted an Islamic state attack that included plans for a series of attacks on security installations, shopping malls, and moderate religious figures last November, state media said.
The security forces have been drawing increasing attention since early this year that sympathizers of the Islamic State could launch revenge attacks after the militants were expelled from most of the territory they once controlled in Syria and Iraq.
King Abdullah, a Middle Eastern ally of Western powers against Islamist militancy, who has also secured Jordan's peace treaty with Israel, is among the loudest leaders in the region, warning of threats from radical groups.
Jordan plays a prominent role in the US-led coalition against the Islamic State, which provides military, logistical and intelligence support, according to Western diplomats and regional intelligence sources.