Shooting into the air and hurling cans of tear gas, about 200 Palestinian security personnel broke up a rally at the West Bank's largest university protesting the arrests of suspected Hamas activists. At least five students were arrested in the Hamas-organized protest at Al Najah University, whose student council is dominated by members of the militant Muslim group. Security forces threw tear gas canisters into the student union, and Israel's Army Radio said four students were taken to hospitals to be treated for inhaling the fumes. The incident was the most serious this month between Palestinian police and protesters demanding the release of suspected Islamic militants jailed in recent sweeps. Police have cracked down on Hamas since the group claimed responsibility for the recent wave of suicide bombings inside Israel.