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The nation's biggest commercial nuclear power facility faces a possible terrorist threat, Energy Secretary Spencer Abraham said Thursday.

Abraham told the Senate Armed Services Committee that terrorists may have targeted the Palo Verde nuclear power plant in Arizona. He said he couldn't go into details about intelligence reports concerning the plans that may have included an attack on the plant.

The Washington Times reported Thursday that terrorists have targeted the Arizona plant and security officials are looking for Iraqi government "sleeper cells" that might carry out the attack. The threat to the facility came from sensitive information indicating that the plant was targeted by Middle Eastern terrorists who were not further identified, the report said.

Arizona Homeland Security Director Chuck Blanchard said he's "heard no evidence of any sleeper cell anywhere in the country."

A Palo Verde spokesman said he couldn't comment on any intelligence reports.

Sen. John Kyl, R-Ariz., chairman of the Senate Judiciary Committee Subcommittee on Terrorism, Technology, and Homeland Security said that he has been assured by the Director of Counterterrorism at the FBI that their investigation into the security of Palo Verde "is proceeding appropriately and that all necessary precautions are being taken."

Palo Verde is the largest nuclear power facility in the United States, containing three reactors that produced 30 billion kilowatt hours of electricity last year.

"We understand the sensitivity of this time, and we are very, very committed to protecting the safe operation of Palo Verde," said Jim McDonald, a spokesman for the Arizona Public Service Co., which owns the reactor complex.

On Tuesday, the day after President Bush formally gave Iraqi President Saddam Hussein an ultimatum -- get out of Iraq within 48 hours or face war -- Arizona Gov. Janet Napolitano sent National Guard troops to help protect the desert plant, located about 50 miles west of downtown Phoenix.

Federal officials said they are also extending their assistance to protect the reactors.

"Authorities from Department of Homeland Security and the FBI are working with local authorities to address the threat information," said Department of Homeland Security spokesman Gordon Johndroe said Thursday.

When asked if that means there was in fact a specific terrorist threat against the facility, Johndroe replied, "That's what I just said."

When the president announced an ultimatum Monday night, the Homeland Security Department ordered the threat level raised to orange -- the second highest level, also known as a high threat of attack. Since then, some states, including Arizona, have been raising their threat levels to match the national alert.

"I want Arizonans to know that we are as prepared as possible to handle any emergency that may arise as a result of heightened tensions in Iraq. I have been working with my Cabinet and my Homeland Security Director to ensure that we are as safe, prepared, and well-guarded as possible for the weeks and months ahead," Napolitano said Tuesday.

Blanchard said guard units were ordered to Palo Verde because Homeland Security Secretary Tom Ridge asked states with nuclear power plants to beef up security.

While war is raging in Iraq and reports continue to come forth stating that Iraqi troops are setting oil fields on fire, Abraham said separately Thursday that world energy supplies are stocked up enough to cover any losses during the war.

"The United States and our International Energy Agency partners are determined to foster stability in world oil markets," Abraham said in a statement.

He said that countries such as Saudi Arabia have been "significantly" boosting their production numbers and tanker loading recently but that "we welcome additional steps by producing countries to make additional supply immediately available to the market as a precautionary measure."

Abraham said he hoped the Organization of the Petroleum Exporting Countries and other major state oil producers "will act to prevent any shortage."

The United States has 599 million barrels of oil in reserve, and -- combined with IEA governments -- have about 1.2 billion barrels.

Abraham said he's confident that between the responses by OPEC and other countries and the stockpiles, "our economy will have the ample supply of energy it needs."

President Bush and close advisers such as Defense Secretary Donald Rumsfeld have warned Saddam and his troops not to destroy Iraq's oil wealth by strategically setting oil fields ablaze.

"Needless to say, it is a crime for that regime to be destroying the riches of the Iraqi people," Rumsfeld said Thursday during a press briefing.

Abraham said the extent of damage to the three or four oil wells said to be on fire is unknown; nor do he know the Iraqi regime's orders on what to do with other wells.

"The United States and its international partners anticipate that Saddam Hussein's regime might attempt acts of sabotage against oil wells. By doing so, Saddam is destroying the wealth of his own people," Abraham said.

"As the president said, those responsible for acts of sabotage will be held to account for their crimes."

Fox News' Liza Porteus and The Associated Press contributed to this report.