Israeli troops blew up a weapons smuggling tunnel on the border between Egypt and the Gaza Strip yesterday, the seventh such tunnel to be discovered along the volatile border since the beginning of the year, the army said. According to the army, about 80 smuggling tunnels have been found in the area since the outbreak of the latest Intifadha. Israeli troops regularly patrol a narrow strip between Egypt and the southern end of the Gaza Strip. The tunnels go under the patrol road and emerge in the Rafah refugee camp. Since 2000, Israeli troops have repeatedly raided Rafah and razed scores of homes near the border. Meanwhile, in the West Bank, a 16-year-old Palestinian boy lost an arm when an explosive device he threw at Israeli soldiers nearby blew up prematurely, witnesses said. The incident began when three Israeli jeeps entered the Balata refugee camp near the West Bank city of Nablus in what the army said was a routine patrol. In another incident, Israeli troops killed three Palestinians on a road it declared off-limits outside a Jewish settlement in the Gaza Strip. Medics who recovered the bodies on Monday said the men were unarmed. Meanwhile, Palestine Liberation Organisation (PLO) has asked Hamas to join a decision-making body to run the Gaza Strip if Israel pulls out, Palestinian officials said yesterday. Hamas is a powerful force in the territory that Israel has held since the 1967 Middle East war, but which Prime Minister Ariel Sharon now aims to quit under a plan to "disengage" from the Palestinians. Sharon has backed away from a personal pledge to US President George W Bush not to harm Palestinian leader Yasser Arafat. Sharon, in a series of media interviews, also said his unilateral plan to remove all Jewish settlements in the Gaza Strip but no more than four in the West Bank could delay "for many years" the creation of a Palestinian state. "I am not vouching for his physical safety," Sharon said of Arafat. "Whoever kills Jews or orders Jews and Israeli citizens to be killed...is a marked man," Sharon told Ynet, the website of Israel's Yedioth Ahronoth newspaper. Sharon acknowledged that he had promised Bush not to harm Arafat physically. But he said: "There have been changes since then." Arafat brushed off initial remarks on Friday in which Sharon threatened him with assassination, saying he was more concerned for his people than for himself. **PHOTO CAPTION*** Blowing up a tunnel on the border between Egypt and the Gaza Strip.