Lebanese officials say the Islamic militant group Hezbollah has handed over to authorities the gunman who shot at an army helicopter Thursday, killing an army officer.

The identity of the person was not provided.

Hezbollah earlier Friday called the incident painful and regrettable, and said it would fully cooperate with an investigation in the matter. The Shi'ite group did not confirm whether it was involved.

The Lebanese newspaper As-Safir reported that Hezbollah fighters opened fire after mistaking the helicopter for an Israeli aircraft that was attempting to land in the southern Hezbollah stronghold of Iqlim al-Tuffah.

The helicopter was on a training mission Thursday when it came under fire and was forced to make an emergency landing in the village of Sejoud.

The Lebanese army deployed in the southern region, along with a reinforced United Nations peacekeeping force, after Israel's war with Hezbollah in 2006.

Some information for this report was provided by AFP and Reuters.