Palestinian Authority security officers on Saturday opened fire at a student demonstration in Ramallah, injuring one person. Dozens of students from Bir Zeit University converged on the Mukata "presidential" compound in the city to protest against the arrest over the weekend of six of their colleagues by the PA's Preventative Security Force. PA officials said the six were all members of the Islamic Jihad organization, which claimed responsibility for last week's suicide attack in Hadera. They said none of the detainees had been directly linked to the attack. Eyewitnesses said the demonstrators tried to force their way into the Mukata to deliver a letter of protest to PA chairman Mahmoud Abbas against the arrests, but were repelled by PA policemen, who used live ammunition to disperse them. Meanwhile, sources in the Gaza Strip reported that Islamic Jihad leaders and activists have gone underground for fear of being targeted by Israel in response to the Hadera bombing. The organization's top five leaders - Khaled al- Batsh, Mohammed al-Hindi, Khader Habib, Nafez Azzam and Ibrahim Najjar - have not been seen in public since the Hadera attack, the sources said. "They have all left their houses and are hiding in safe homes," said one source. "They have even stopped using their mobile phones."