Hamas gunmen opened fire at pro-Hamas protesters at a rally on the Gaza-Egypt border Saturday, killing a teenager, hospital officials said. Tens of thousands of flag-waving Hamas supporters gathered at the Rafah border crossing with Egypt on Saturday to demand it be reopened. The border, Gaza's only gateway to Egypt, has been shut since Hamas' bloody takeover of the Gaza Strip in June. Hamas gunmen guarding the border fired in the air as hundreds of protesters tried to rush the border terminal and attempted to infiltrate into Egypt. A 17-year-old was shot in the head and was later pronounced dead, medics said. Seven others were wounded by gunfire and trampling. "This is a peaceful protest to voice our message that we are looking for freedom," said Issa Mashar, a top Hamas leader in Rafah. "We came to send a message from the people who are suffering." But when hundreds of Hamas supporters tried to storm the crossing, Hamas militiamen staved them off by firing in the air. Asharaf Abu Aya, one of the rally's organizers, appealed for calm from the crowd. "There is no need to break into the crossing. The crossing is no longer under the occupation. The crossing is under the control of the Hamas Executive Committee," he said. Also Saturday, Hamas authorities set a hefty bail for the release of the Fatah activists it arrested following a Gaza protest rally. Hamas overthrew Fatah in five days of fighting in June, overtaking the Gaza Strip, and has since been attempting to establish its authority and thwart any forms of dissent. On Friday, Hamas men violently dispersed a crowd of Fatah protesters, firing in the air and beating demonstrators. Some 20 people were wounded in the clashes, including two French journalists and two children, according to doctors and witnesses. Scores of protesters were arrested. The violence began at the end of a Fatah prayer session it held outdoors to protest against Hamas, which it says is persecuting its members in Hamas-controlled mosques. The PLO Executive Committee, a top Fatah decision-making body, was set to meet later Saturday in Ramallah upon the request of Palestinian Authority Chairman Mahmoud Abbas to discuss Friday's clashes in Gaza. It was expected to denounce Hamas for its aggression against the Fatah protesters. Fatah officials said 170 of its members remained in Hamas custody Saturday. Some of those released emerged from their arrest with their heads shaved - a humiliating gesture. Hamas said it released most of those arrested and that only about 20 remained in detention. But Hamas demanded a 1,000 shekel bail for the release, about a month's salary in the impoverished Gaza Strip, where 60 percent live under the poverty line. "I consider this a theft. What is the crime I committed?" said Ahmad Siam, 33, whose father paid the sum for his freedom. "I didn't commit a crime to pay that money." Ihab al-Hussein, a Hamas security spokesman, said the money would be reimbursed in six months if the offenders pledged not to resume "rioting or illegal activities." "This is a legal measure. It is a way to bring the person to reconsider his action. Money might be the way to prevent these chaotic acts," he said. The legal system in Gaza stopped functioning after Hamas took over the coastal strip in June. Abbas fired the Hamas-led government, formed a new government in the West Bank and ordered judges, prosecutors and police to stop cooperating with Gaza's new rulers. Last week, Hamas appointed its own prosecution team in Gaza, which Saturday imposed the hefty bail. Ibrahim Abu Naja, a Fatah official in Gaza, said his group would not pay up. "This is a serious precedent," he said. "The decisions adopted are illegal. This is tantamount to occupation (laws)," he said, referring to Israel's rule over the Gaza Strip, which ended in 2005. Families of some detainees said they could not afford to pay the bail, and said they would organize another rally if their sons were not released. Khalil Abu Shamala, a human rights activist in Gaza, said both the detention and the bail demand were illegal. "The whole legal system in Gaza is destroyed and defunct," he said. "On what basis can they arrest, detain, question and then set bail?"