Palestinians in Gaza fired four Kassam rockets at the western Negev on Tuesday morning , the rocketslanded in an open area, there were no reports of injuries or damage. The Islamic Jihad later claimedresponsibility saying it launched the rockets in response to the IDF operation in Jenin during whicha senior Islamic Jihad operative was killed. In response to the rocket fire, Defense Minister Ehud Barak order the Gaza bordercrossings to be shut down Commenting on the truce while visiting an armored corps drill in the GolanHeights, Barak said calm will be met with calm, but if deemed necessary Israel is prepared to launcha military operation in the Gaza Strip12/16/08