Israeli warplanes pounded six Arab guerrilla camps and Israeli-backed Lebanese troops seized a strategic hilltop in the biggest blitz of the year against pro-Iranian and Palestinian forces in southern Lebanon. Security sources and guerrillas said at least 19 people were killed and 40 others wounded, including women and children, in the air strikes and ground assaults Wednesday. In the Iraqi capital of Baghdad, PLO Chairman Yasser Arafat said recent Israeli air strikes in southern Lebanon were in preparation for a large-scale attack against Palestinian refugee camps.