Israeli troops fatally shot two Palestinians who infiltrated the country from Gaza and in a separate incident killed another Palestinian who tried to breach the border Sunday night, the military said. Another Palestinian was detained in the latter incident, and two more were caught trying to cross the border in a third case, the military said. The Gaza border has been tense in recent weeks, with Hamas group urging mass Palestinian protests there every Friday as part of a weeks-long campaign against a decade-old blockade of the territory. The military said that "two terrorists who infiltrated into Israel hurled explosive devices" at soldiers Sunday night. The soldiers returned fire, killing them. About a half hour earlier, two Palestinians damaged the security fence and tried to cross into Israel. Troops opened fire, killing one, the military said. The other was detained for questioning, it said. In a third incident, soldiers spotted two Palestinians trying to breach the border. They were arrested and found to possess knives and wire cutters, the military said. Israel has been accused by the United Nations, European Union and rights groups of using excessive force against unarmed protesters. Israel said it is aiming only at instigators, and accused Hamas of using civilians for cover to carry out attacks. Israel said some of those protesting have tried to damage the border fence or plant explosives along it. Others have hurled improvised explosives and firebombs at soldiers while others have flown kites with burning rags attached to set Israeli fields on fire. Israeli forces have killed 42 Palestinians since protests began on March 30 and some 2,000 have been wounded by gunfire. No serious casualties have been reported on the Israeli side. The protests also press for a "return" of Palestinian refugees and their descendants to what is now Israel. Hundreds of thousands of Palestinians fled or were displaced in the 1948 war over Israels creation. The protests are to culminate May 15, the anniversary of Israels founding. Palestinians mark the date as their nakba, or catastrophe.