Two American military personnel and one South African were killed and six others injured when a Jordanian officer went on a shooting spree on Monday at a US-funded security training facility near Amman, Jordan's government spokesman said.
Mohammad Momani also told Reuters the attacker had been shot dead by Jordanian security forces and did not commit suicide, as was previously reported. The shooter was a senior co-trainer with the rank of captain, another source said.
The six injured included another two Americans, one critically wounded. The incident took place in a facility that mainly trains Iraqi and Palestinian forces on the outskirts of the capital Amman.
It took place on the 10th anniversary of al Qaeda suicide bombings that targeted three Amman luxury hotels, killing dozens of people in the worst militant attack in Jordanian history.
The United States is in contact with Jordanian authorities about the incident, the US State Department confirmed.
Jordan is a staunch US ally and part of the Washington-led coalition that is trying to defeat the Islamic State (IS) in Syria and Iraq, both of which border Jordan.
The country hosts several hundred US trainers who are part of a military program to bolster the kingdom's defences, including the stationing of F16 fighter jets that use Jordanian airfields to hit IS positions in Syria.
But the kingdom's role in the war against IS has caused disquiet among some Jordanians worried about instability at their borders and fearing that a stepped-up role in the campaign might lead to Islamist attacks in their country.
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