New York, June 01: Two or three al-Qaeda terrorist cells are still operating in Saudi Arabia despite a "frenetic investigation" and at least 11 arrests since the May 12 Riyadh bombing, a media report said today quoting officials. FBI director Robert Mueller will make an unannounced visit to Saudi Arabia this week to thank the Saudis for their cooperation and keep up the momentum, time magazine says in its upcoming issue. A US/Saudi task force has already conducted more than 400 joint interviews, ending laws that forbid foreigners from questioning Saudi citizens, and FBI is working closely with its Saudi counterparts to collect explosive residue and other forensic clues in the Riyadh wreckage, it reported. Relations improved after FBI director Louis Freeh made a number of trips to Saudi Arabia, and on June 21, 2001, the justice department obtained an indictment charging 13 Saudi members of Hezbollah and one unidentified Lebanese man with complicity in the bombing. The indictment charged that an Iranian military officer had directed two of the defendants to conduct surveillance on Saudi Arabia's Red Sea coast for likely places to attack Americans, the magazine said. Now that cooperation is improving, US is sharing sensitive intelligence with the kingdom in "real time". Acting on such intercepts, Saudis last week captured two Moroccan al-Qaeda suspects who had just arrived in Jeddah, say sources familiar with the investigation, the report said. Meanwhile, in Riyadh, security forces arrested five more people in connection with the Riyadh suicide attacks, a newspaper reported yesterday. Bureau Report