JERUSALEM - Two Israeli soldiers and two Palestinians were killed in an exchange of fire along Israel's border with the Gaza Strip on Friday after an Israeli army patrol spotted Palestinians planting explosives along the border, the army said. The Israeli deaths were the first military casualties since shortly after Israel completed a three-week military offensive in the Gaza Strip in January 2009 that aimed to stop the firing of rockets from Gaza into Israel. Two other soldiers were wounded in Friday's incident. Three Palestinian groups issued statements taking responsibility, including the military wing of the ruling Hamas movement, Izzedine al-Qassam Brigades, the al-Aqsa Martyrs Brigades, and a little-known group that called itself Palestine Taliban.