In the Mediterranean Theater, the Italian air force was invoked in air strikes against Malta, targeted on British merchant ships and naval units operating near Italy. It also conducted raids against Gibraltar and Palestine and even as far afield as the Persian Gulf. However, the Italians soon learned that aircraft that had been successful against stationary merchant ships docked in harbors during the Spanish Civil War were ineffective in high-altitude bombing attacks against warships. Indeed, early in the war, the aircraft occasionally attacked Italian warships by mistake, although recognition improved as the war unfolded. But not until March 1941 did the air force place liaison officers on board warships at sea.