TEL AVIV — Osama Bin Laden appears to be dead but his colleagues have decided that Al Qaida and its insurgency campaign against the United States will continue, Israeli intelligence sources said. Al Qaida terrorists have launched a new campaign of economic warfare and are targeting shipping in the Middle East, according to U.S. intelligence officials. The Israeli sources said Israel and the United States assess that Bin Laden probably died in the U.S. military campaign in Afghanistan in December. They said the emergence of new messages by Bin Laden are probably fabrications, Middle East Newsline reported. But Bin Laden`s heir has been chosen and his colleagues have decided to resume Al Qaida`s offensive against the United States and Western allies, the sources said. They said the organization regards the United States as the main target followed by Israel. "In this case, it doesn`t matter whether Bin Laden is alive or not," a senior Israeli intelligence source said. "The organization goes on with help from key people." The sources said Al Qaida has already determined Bin Laden`s heir. They said the heir has not been identified, but is probably not Bin Laden`s son, Saad. Saad is said to be in his 20s and ranked within the top 20 members of Al Qaida. Earlier this week, Bin Laden`s deputy, Ayman Zawahiri, was said to have released a videotape in which he claims that the Al Qaida leader is alive and functioning. Bin Laden`s voice was not heard on the tape. A senior Bush administration economic official said last week that another major Al Qaida attack anywhere in the world could have devastating economic repercussions. The FBI warned last week that Al Qaida may be preparing for a major attack. The warning followed the release of an audio tape featuring the voice of Zawahiri. Bombings in Bali aimed at tourists, an attack on U.S. soldiers training in Kuwait and the bombing of a French tanker in Yemen are signs of the new campaign, Geostrategy-Direct.com reported in its Oct. 22 edition. The first attack was carried out last week with the Al Qaida terrorist attack on the French tanker Limburg, a 157,000-ton ultra large crude oil carrier, that was bombed as it picked up a pilot before mooring at the Yemeni port of al Shihr. One crew member was killed and others were injured in the blast. According to intelligence officials, a small boat approached at high speed from the starboard side of the ship and detonated a large explosive device. A week earlier, the Office of Naval Intelligence issued an alert to ships in the Middle East to be alert for Al Qaida terrorist attacks.