Nahal Brigade soldiers discovered some 30 kilograms of explosives belonging to the Islamic Jihad movement on Wednesday morning in a weapons laboratory in the village of Bourkin near Jenin. The material was described as being 'ready for use', and it was found along with parts for constructing explosive devices. Sappers blew up the laboratory in a controlled explosion. Police were at their highest level of alert in expectation of the Passover holiday and, according to Israel Radio, there were some 70 warnings, most of them of a general nature, regarding plans by terror organizations to carry out attacks inside Israel. IDF forces were fired at early Wednesday in two separate incidents near the West Bank cities of Nablus and Tulkarm. No one was wounded and no damage was caused. Meanwhile, the IDF fired artillery shells towards Kassam rocket launch sites in the Gaza Strip. The IAF attacked a building in Gaza City overnight Tuesday which was used as an al-Aksa Martyrs' Brigades headquarters. No one was wounded. The IDF said terror attacks were being planned from the location and that it was used as a centre for the recruitment of al-Aksa operatives. Also on Tuesday night, troops arrested 12 fugitives from the Fatah, Hamas and Islamic Jihad organizations throughout the West Bank. The IDF showed no signs of moderating its stance in the current offensive against Palestinian terrorists. "We will continue to act strongly in order to prevent attacks against Israeli citizens" said an army spokesman.