BAGHDAD, July 19 (Xinhua) -- Unknown drone bombarded on Friday a paramilitary Hashd Shaabi camp in Iraq's central province of Salahudin, wounding at least three Iraqis and two Iranians, a local security source said.

The attack took place before dawn when unknown drone bombarded the headquarters of 52nd Brigade of Hashd Shaabi, which is located near the town of Amirli near the town of Tuz-Khurmato, some 90 km east of the provincial capital Tikrit, the source said on condition of anonymity.

The brigade is for elements from the Iranian-backed Badr Organization, headed by the Shiite leader Hadi al-Ameri, the source said.

Badr Organization was previously known as Badr Brigade which maintains its longtime ties with the neighboring Iran, where it was first built during the eight-year Iraqi-Iranian war in 1980s.

Ameri's Brigade turned to be a political organization after 2003 U.S.-led invasion of Iraq.

The attack resulted in the wounding of three Iraqi militiamen and two Iranian advisors in the Hashd Shaabi brigade, according to the source.

Later in the day, the media office of the Iraqi Joint Operations Command (JOC) confirmed the attack of the unknown drone and put the toll at two people wounded, without giving further details.