BEIRUT (AFP) - Lebanese anti-aircraft guns opened fire on four Israeli warplanes, which were violating its airspace at low altitude on Sunday, the military said. The armys anti-aircraft guns fired at four Israeli warplanes overflying southern Lebanon, Hasbaya, the Shouf and the Bekaa, all in southeastern Lebanon, an army statement said. The incident came amid heightened concern in Lebanon over recent Israeli threats against Hezbollah and its backer Syria. Prime Minister Saad Hariri described Israeli military activity as escalating and really dangerous in a BBC interview broadcast Wednesday. During the past two months, every day we have Israeli planes entering Lebanese airspace, Hariri said.