Jordanian police captain shoots foreign and local military personnel before being gunned down.
A Jordanian police captain shot dead two Americans and one South African at a police training centre near the capital, reports said.
State news agency Petra said on Monday that the three foreign instructors killed were on contract with Jordanian police.
At least two Jordanians were also killed in the attack, Petra said.
The attacker’s colleagues shot the gunman dead following the incident, reports said.
US President Barack Obama said a “full investigation” would be set up and the US was “working closely with Jordanians”.
Pentagon Spokesman Major James Brindle told Al Jazeera that the Pentagon was trying to verify information, adding that he could not yet confirm the identity of the two dead Americans.
The police training centre is in Al-Mowager, 30km from Amman, and mainly trains Iraqi and Palestinian forces.
The attack coincides with the 10th anniversary of suicide bombings in Amman hotels that cost 60 lives and wounded dozens more.