Working on a tip, police stormed a hideout in east Amman where the suspects had been hiding, the police said in a statement carried by the official Petra news agency, according to the Associated Press.
The militants — one Jordanian and two foreigners — were killed after they refused to surrender and opened fire on police in the predominantly Palestinian district of Hashemi.
Witnesses said paramilitary police surrounded the area and cordoned off streets near the house after the shootout, Reuters reported.
Security officials who spoke to wire services on condition of anonymity said the three killed were suspected of having ties to a terrorist group planning to attack the prime minister’s office and Jordan’s secret service with a chemical bomb last month, a plot that was revealed last week.
Had the bomb exploded, it could have killed at least 20,000 people and leveled buildings within a half-mile radius, government officials have said.
The clash was the most serious since the authorities cracked down this month on a militant group accused of planning attacks on the U.S. Embassy and other government installations, security sources said.
Since the bombing and chemical plots were revealed, police have arrested an unspecified number of suspects and seized at least three cars filled with explosives and detonators.
Jordan, a moderate Arab nation that has supported Washington’s efforts to pacify post-war Iraq, has been targeted by Osama bin Laden’s terrorist network al-Qaida and other militant Islamic groups.