Hundreds of alleged members of al Qaeda, including 18 of its top leaders, and other terror groups are living in Iran, some under tight security, Asharq Al-Awsat newspaper reported Thursday.
"More than 384 members of al Qaeda and other terrorist organisations are present in Iran, including 18 senior leaders of Osama bin Laden's network," the London-based daily said, citing a senior source in the Iranian presidency.
The Saudi-owned newspaper said the terrorist leaders were living under tight protection, some of them in villas in the Namak Abrud region, near the town of Chalous on the Caspian coast, 100 kilometres (60 miles) north of Tehran.
Others are living in Lavizan, in the north-west of the capital, and which also houses a large military complex, it added.
The report could not be verified in Tehran.
According to the source, Syrian President Bashar al-Assad convinced Tehran, during his visit to Iran early this month, of the "seriousness" of using al Qaeda elements in Iran as a card in its policy with the United States.
As a consequence, Tehran handed over wanted Saudi militant Khaled bin Odeh bin Mohammed al-Harbi to the Saudi authorities, the source added.
Riyadh has said the disabled militant, suspected of being an al Qaeda figure close to bin Laden, surrendered on Tuesday under an amnesty after contacting the Saudi embassy in Iran.
In 2003, Iran confirmed it was holding senior al Qaeda members but refused to identify them. Tehran has said the detainees may stand trial in Iran.
Iranian Foreign Minister Kamal Kharazi said last month his country had given Saudi Arabia some useful information concerning members of Osama bin Laden's network that it was detaining.