Ten nations and Lebanon's Hezbollah have been supplying weapons to an Islamic militia that controls much of Somalia, violating an international arms embargo, according to a U.N. commission report obtained Wednesday.

But experts and diplomats expressed deep skepticism about an allegation in the report that 720 Somali mercenaries fought alongside Hezbollah in its battle with Israel in July. There were also doubts about the U.N. panel's findings that Iran shipped arms to the Islamic militants in return for access to uranium mines in the hometown of the top Islamic leader.

The Iranian government, in a letter to the U.N., also strenuously denied shipping weapons to Somalia.

The U.N. panel, charged with monitoring the arms embargo on Somalia, said Ethiopia, Eritrea, Egypt, Yemen, Libya, Iran, Djibouti, Saudi Arabia, Syria and Uganda had all supported armed groups inside Somalia.

"At the time of the writing of the present report, there were two Iranians in Dhusa Mareb engaged in matters linked to uranium in exchange for arms," said the report, which has not been released to the public. Iran also supplied an aircraft to fly 40 Somalis wounded in Lebanon back to Somalia, it added.

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A Hezbollah official, speaking on condition of anonymity because no formal statement from the group has been released yet, dismissed the report as "totally baseless."

Hezbollah is an extremely secretive Shiite organization that does not recruit foreigners to join its ranks. The group is also fervently Shiite, which clashes theologically from the fundamentalist Sunni sects practiced in Somalia. There have been no other reports of any Africans fighting in Lebanon.

The Islamic courts only had about 2,000 trained militiamen when the fighting in Lebanon took place in July, so it seems unlikely they would send their best men out of the country when they were needed at home.

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 expressed skepticism about the report's allegations of Somalia's ties to Iran and nuclear issues.

Somalia's Council of Islamic Courts has competed directly with an internationally backed government, which so far has failed to assert itself outside of one town. Some of the courts' leaders include men that the United States and the United Nations have linked to al-Qaida, Osama bin Laden's terrorist group.

Both the government, which is backed by Ethiopia, and the courts, which are backed by Eritrea, have been preparing for an all-out war for control of Somalia, the report concluded. Mediators from East Africa and the Arab League have been working frantically to reach some kind of peace deal, but so far without success.

"The contest is overwhelmingly military in nature, with rampant arms flows to both sides," the U.N. report said. "The arms flows are a premier part of a deliberate, ongoing and broader military build up taking place on both sides."

The authors of the report called on the international community to being closely monitoring Somalia's coastline and land borders to intercept suspected arms shipments. The U.N. Security Council resolution that imposed the embargo does not authorize any methods to enforce it. The authors of the report also noted that none of their recommendations in the past 15 years have been implemented.