Quds city, April 29, SPA -- Palestinian security officials detained four extremists for questioning after a barrage of mortar shells and homemade rockets were fired at Jewish settlements in the Gaza Strip this week, Palestinian security officials said Friday. The four members of the Al Aqsa Martyrs' Brigades, were called in for questioning Thursday, the officials said. Al Aqsa officials said they had not heard from the men since they were detained. Abbas and Israeli Prime Minister Ariel Sharon agreed to a cease-fire in February, calling a halt to more than four years of violence between the two sides.