Two Americans and a South African have been shot dead by a police officer at a security training facility in Jordan, according to a security source.

The officer reportedly went on a shooting spree at the US-funded facility for training Iraqi and Palestinian security forces in Al Muwaqqar on the outskirts of the capital Amman.

Conflicting reports suggest the police officer committed suicide or was shot and killed following the attack.

Jordan's government-owned Al-Rai newspaper reported that up to six people were injured in the attack.

Jordan, which is a staunch ally of the US, is home to several hundred US security trainers who form part of a military programme to bolster the country's defences, US F16 fighter jets have been using Jordanian airfields to hit Islamic State positions in Syria and the kingdom's role in the war has concerned some Jordanians who are worried this could lead to Islamist attacks in their country.

In February, Jordan killed Iraqi would-be suicide bomber Sajida al Rishawi after Islamic State killed Jordanian pilot Mu'ath Al Kassasbeh.

No further information has become available and neither the US embassy or the Jordanian government was available for comment.

An anonymous source told the Jordan Times newspaper: "It is yet not known whether the shooting was because of a dispute between the policeman and the contractors," adding that an official announcement would be made by authorities later in the day.