Quds city, Nov 12, SPA -- Israeli police canceled all leave and went on their highest state of alert Friday, fearing unrest and riots during the funeral for Palestinian leader Yasser Arafat, police said. "We have thousands of policemen on duty, basically the whole police force," said police spokesman Gil Kleiman. "We are on our highest level of mobilization," he said. Overnight, police arrested 21 people after clashes in Al-Qud's Arab neighborhoods. Security focused on Al-Quds's Old City where thousands of Muslims were expected to gather at the Al Aqsa and Dome of the Rock mosques for prayers marking the last Friday of the holy month of Ramadan.