A Marine Corps AV-8B Harrier has struck an Islamic State target near the Haditha Dam in Iraq.

A defense official, speaking on the condition of anonymity, said the strike occurred on Monday, and involved a Harrier from the 22nd Marine Expeditionary Unit operating from the amphibious ship Bataan.

It was the first time that a Marine unit dropped ordnance in the current fight against Islamic State, the defense official said. Militants want to take control of the dam in order to have influence over water, a scare resource in Iraq, and hydro-electric power. Once the center of a bitter contest between Marine grunts and al-Qaida militants during the Iraq War, Haditha Dam is strategically situated along the Euphrates river in Iraq's western Anbar province, right in the middle of territory contested by IS.

The large majority of Harrier sorties from the Bataan have been for "non-traditional" intelligence, surveillance and reconnaissance purposes, officials say, and during the ongoing attacks against Islamic State, AV-8Bs Harriers from the 22nd MEU in the Bataan ARG have quietly provided surveillance. Non-traditional ISR includes surveying terrain and potential targets, but aircraft are also armed and can attack if needed, officials said.

There have been "dozens" of intelligence, surveillance and reconnaissance sorties flown from the Bataan, United States Naval Central Command spokesman Lt. Joe Hontz said.

The MEU's Harriers are supporting strikes in the country, but the jump jets are also armed and can launch an attack if needed, Hontz said.

He couldn't say if a Harrier ISR sortie resulted in an attack from another aircraft and said that the Harriers were not on station for the assessment of Mt. Sinjar where a religious minority group had sought shelter after militants destroyed their homes.

"We cannot discuss the details of the (non-traditional intelligence, surveillance and reconnaissance) missions other than to confirm that 22 MEU's Harriers have conducted them," he said.

While Harriers are providing some of the surveillance, defense analysts, however, said that the Air Force is most likely providing the majority of the surveillance, particularly in Syria. The Air Force is likely using the U-2 Dragon Lady,the unmanned RQ-4 Global Hawk and the unmanned RQ-170 Sentinel.

The 22nd MEU's surveillance flights started on July 27 and the Bataan Amphibious Ready Group extended its deployment by 21 days in order to stay in the 5th Fleet until the beginning of October. Besides the big-deck amphib and MEU, the ARG includes amphibious ships Mesa Verde and Gunston Hall. Airstrikes started on Aug. 8. Most of the naval sorties originated from the carrier George H. W. Bush.