Soldiers from the Nahal reconnaissance regiment uncovered an explosives laboratory during a sweep of Nablus's old city Friday night, military officials said. According an IDF spokesperson, troops found several "simple" devices ready for use, sacks of explosive material, and sheets of cardboard coated with glue and covered with screws and bolts. Sappers destroyed the materials in a controlled explosion. During the operation in Nablus, an improvised explosive device was thrown at troops from the Golani infantry brigade, causing no wounded or damages. Soldiers arrested a total of four Palestinian fugitives during seperate counter-terror operations Friday in the West Bank, the army said.