MUSCAT, Oman (AP) _ A Russian tanker detained by the U.S. Navy on suspicion it was violating U.N. sanctions against Iraq headed today to Oman, where experts will determine if the oil on board came from Iraq.

The ship was seized in the Gulf earlier this week because it was suspected to be carrying Iraqi oil. The United States and Russia have been at loggerheads over the matter after Washington spurned a demand by Moscow that it release the tanker.

The vessel, Volga-Neft-147, is expected to arrive late today or early Sunday in Muscat, the Omani capital, and will leave as soon as the oil has been offloaded, an Omani Foreign Ministry official said on condition of anonymity.

The oil will be held pending the completion of an investigation, the official said. Specialists in oil analysis are expected to arrive in Muscat shortly.

Russia maintains the oil is from Iran, not Iraq.

Once the origin of the oil has been determined, Oman, the United States and Russia will decide what should be done with it, the official said.

U.S. officials have said that if the oil is Iraqi, the cargo will be confiscated and sold, with a portion of the proceeds used to pay for the U.N. sanctions monitoring operation.

A Pentagon spokesman, Army Col. Vince Ogilvie, said Friday that two officials from the Russian consulate in the United Arab Emirates boarded the tanker as it sailed in international waters, as did two American defense attaches.

Iraq's government-run Al-Thawra newspaper said in an editorial that the American claim that Iraq benefits from smuggling oil is ``a sheer lie.''

The United States has long been at odds with Russia over Iraq. Russia is a strong supporter of steps toward the eventual lifting of the U.N. economic embargo against Iraq. The Clinton adminstration demands stronger proof from Iraq that it is meeting U.N. Security Council resolutions, including a requirement that Iraq not possess weapons of mass destruction.

The U.S. officials have argued that the administration was merely enforcing the embargo against Iraq in ordering the seizure Wednesday of the Russian vessel, saying U.N. resolutions authorize seizures in cases where smuggling is suspected.

Iraq is banned from most international commerce but is allowed to export up to $5.2 billion in oil every six months in order to buy food, medicine and other essentials for its people, and spare parts for its oil industry.

Despite the effort to enforce the U.N. sanctions, the U.S. State Department said Thursday that illicit oil exports from Iraq average 100,000 barrels a day, compared with 50,000 barrels in 1998, when oil prices were much lower.

Iraqi officials deny smuggling crude oil or by-products. Iraq says the United States scrutinizes Gulf ships traveling to and from Iraq, but does nothing to stop brisk oil smuggling over land from northern Iraq _ a Kurdish area outside the Baghdad government's control _ into neighboring Turkey, a U.S. ally.