The Washington post said on Wednesday that it had obtained the confidential U.N. report which was prepared by a panel of U.N. weapons and financial experts.
Hizbullah's senior political officer in south Lebanon rejected the report as "baseless."
"It's an absurd report that does not warrant a comment," Sheikh Hassan Ezzeddine told The Associated Press.
Hizbullah is fervently Shiite Muslim, which theologically clashes with the Sunni form of Islam practiced in Somalia. There have also been no other reports of any Africans fighting in Lebanon.
Somalia's Islamic movement only had about 2,000 trained militiamen when the fighting in Lebanon took place in July, so it seems unlikely it would send out so many men when it was still consolidating across southern Somalia.
Ted Dagne, a Somalia expert at the Congressional Research Service in Washington, said he questioned some of the report's contents.
"It would be hard not to notice a black man fighting in Lebanon," he said, adding that he also doubted significant Iranian involvement within Somalia. "The Saudis are probably more active than the Iranians."
A diplomat who has closely followed developments in Somalia also found errors in the report's details on certain arms shipments. Speaking anonymously because of the sensitivity of the issues, he questioned the ties to Iran and nuclear issues.
"There is a lot misinformation flowing around Somalia right now, so we must be very skeptical" the diplomat said.
The U.N. report said that Iran also supplied an aircraft to fly 40 Somalis wounded in Lebanon back home to Somalia.
The report said Iran, Syria, Libya and Hizbullah are providing arms, training and financing to Islamic militants as they seize political and military control in the East African state of Somalia.
To shore up support for their cause, Somalia's Islamic fighters provided military support in the summer to Hizbullah, sending 720 of its most experienced fighters to help battle Israeli forces, according to the report. The fighters were promised $2,000 in payments to their families for serving, and as much as $30,000 if they fell in battle.
The report said that in exchange for their backing, Hizbullah provided advanced training to Somali fighters and sent five Hizbullah advisers to Somalia. It also allegedly solicited support for the movement from Iran and Syria.
It warned that the conflict could reignite a war between Eritrea, the chief foreign sponsor of the Islamics, and Ethiopia, which is backing Somalia's weak transitional federal government.(AP-Naharnet)