OCCUPIED JERUSALEM - Israel's military says Gaza gunmen have fired a military-grade rocket into Israel, causing light damage and no injuries. Gunmen from inside Gaza regularly fire small rockets they manufacture themselves and only rarely use military-grade projectiles such as the relatively powerful Grad launched early on Friday. None of the armed groups in Hamas-ruled Gaza immediately claimed responsibility for the attack. An Israeli airstrike this week killed two senior members of one such group, the Army of Islam. Another faction released a video in Hebrew threatening retaliation for their deaths. Rocket fire from Gaza has sharply declined since Israel's offensive in the coastal strip ended in early 2009.