Die Welt said the Iranian Revolutionary Guard released Saad bin Laden on July 28 with the aim of sending him to the Syria-Lebanon border. It linked the reported move to the outbreak of war between Israel and Lebanese-based Hizbullah.
"From the Lebanese border, he has the task of building Islamist terror cells and preparing them to fight together with Hizbullah," Die Welt said, quoting intelligence information.
"Apparently Tehran is counting on recruiting Lebanese refugees in Syria for the fight against Israel, using bin Laden's help," it added in a preview of a report to appear in its Thursday edition.
Western intelligence sources have long suspected that Iran is holding a number of al-Qaeda figures, possibly including Saad Bin Laden and Saif al-Adel, the network's security chief.
Al-Zawahri: Fight and become martyrs
Kamal Kharrazi, then Iran's foreign minister, said in January 2004 that Tehran had jailed about a dozen al-Qaeda suspects and would put them on trial.
"Our general view is Iran certainly does have a few al-Qaeda-related figures ... The general perception is Iran keeps these people as a bargaining chip," said a European counter-terrorism official when asked about the Die Welt report.
He said Shia Muslim Iran was not sympathetic to members of Sunni-dominated al-Qaeda but "they protect them as long as they think they can make use of them."
Al-Qaeda's deputy leader Ayman al-Zawahri issued a video message last week in which, while not mentioning Hizbullah by name, he urged Muslims everywhere to "fight and become martyrs" in response to the conflict in Lebanon.
Israel accuses Iran of providing Hizbullah with missiles to use against civilian and military targets. Tehran, which armed and funded Hizbullah in the 1980s, insists it now provides only moral support to the group.