U.S. forces were on heightened alert in Iraq Thursday, the 35th anniversary of the 1968 revolution that brought Saddam Hussein's Baath Party (search) to power — sparking rumors that the fallen leader would make some sort of public appearance.

The deposed dictator never surfaced -- but his voice may have, as Al-Arabiya (search) satellite television broadcast an audiotape of a man purporting to be Saddam, denouncing Iraq's newly formed Governing Council (search).

The reference to the council, which was formed under the aegis of U.S. administrators and met for the first time Sunday, indicated the recording was probably new.

"How can the people benefit from employees named by the foreign occupiers?" asked the voice. "The occupier has occupied in order to weaken Iraq and destroy its will, and therefore, anything issued by occupation is to weaken Iraq. The only solution ... is a jihad [holy war] to resist the occupation."

Reporters familiar with Saddam's voice said it sounded like him, but there was no independent verification of the audiotape.

In Washington, the new chief of the U.S. Central Command (search), Gen. John Abizaid, acknowledged for the first time Wednesday that coalition forces are facing a "classical guerrilla-type war situation" against opponents ranging from members of the Baath Party to non-Iraqi fighters from terrorist groups.

But "they're not driving us out of anywhere," he said.

The Pentagon reported that as of Thursday, 147 U.S. personnel had been killed in combat since the start of the war, matching the 147 killed in combat during the 1991 Gulf War.

Meanwhile, senior defense officials told Fox News that U.S. troops had unearthed Iraqi secret police documents stating that the current rash of postwar attacks, ambushes and organized chaos against coalition forces had been planned months before the war in Iraq even began.

Though not confirmed, the documents instruct members of the Mukhabarat (search) — the secret police — how to keep fighting after the fall of the regime, and suggest that guerrilla warfare was part of Saddam's strategy all along, the officials said.

By midday Thursday, there was no word of fresh attacks on U.S. troops.

The eve of the holiday saw a marked escalation in attacks that killed an American soldier and the U.S.-allied mayor of an Iraqi city — a chilling warning to Iraqis who cooperate with Americans.

The July 17, 1968 coup brought a coterie of Baath officials to power in Baghdad, and Saddam rose to the top of the heap 11 years later.

Iraq's Governing Council, in its first act Sunday, swept aside the July 17 celebration and five other dates the avowedly secular, socialist and Arab nationalist Baath party marked as official holidays.

Saddam and his two sons, Udai and Qusai, have not been seen since the capital fell April, though he has been heard on several audiotapes in recent weeks.

A tape broadcast July 5 featured "Saddam" telling Iraqis he was in Iraq organizing resistance to the occupation. CIA officials said then that the voice was likely his, but the recording's poor quality made verifying it impossible.

The speaker on the July 5 tape claimed he had been recorded June 14, and also said, "O brothers and sisters, I relay to you good news: Jihad cells and brigades have been formed."

On July 8, several Arabic television channels played another recording they claimed to be new but which was identical in wording to a tape first released in May.

The new tape thanked Iraqis for resisting the coalition's occupation of Iraq, said the Americans and the British lied in intelligence reports to their own people and called on Iraqis to kick the Americans out of the country.

U.S. soldiers have come under increasingly ferocious and frequent attack by suspected Saddam loyalists in recent weeks — reaching an average of 12 attacks a day.

More than 30 U.S. soldiers have been killed in hostile action since President Bush declared an end to major hostilities on May 1.

One surface-to-air missile was fired on a C-130 transport plane Wednesday as it landed at Baghdad International Airport. It was only the second known missile attack on a plane using the airport since Baghdad fell to U.S. forces on April 9, said Spc. Giovani Lorente.

Mohammed Nayil al-Jurayfi (search), who had cooperated with U.S. forces as the new mayor of Hadithah, was killed in an ambush Wednesday. One of the mayor's sons also was killed in the attack 150 miles northwest of Baghdad.

Police Capt. Khudhier Mohammed said the mayor, who took office after Saddam's fall, was slain because he was "seizing cars" from Saddam loyalists who used to work in the deposed Iraqi leader's offices in Hadithah, a city in the restive "Sunni Triangle" that is home to many supporters of the ousted dictator.

The Arab satellite broadcaster Al-Jazeera (search) said residents of Hadithah accused the slain mayor of collaborating with coalition forces.

"This mayor is an unwanted person ... He doesn't belong to this city," said Hadithah shop owner Amir Jafar. "He is from another city and he was cooperating with the Americans."

Former New York police commissioner Bernard Kerik, who is now running the Iraqi Interior Ministry and working to rebuild Iraq's police force, was asked if he thought Usama bin Laden's Al Qaeda terror network was behind the attacks.

"Nobody is identified as Al Qaeda yet. Could they be out there? It's possible. The bottom line is I don't care if they're Al Qaeda, I don't care if they're Fedayeen. I don't care if they are Baathists, I don't care who they are. If they attack the coalition and they attack the police they're going to be arrested or they're going to be killed," Kerik said.

U.N. Secretary-General Kofi Annan and Secretary of State Colin Powell said there were ongoing discussions about a possible U.N. resolution appealing to member states to supply troops and police to help stabilize Iraq.

The talks began after Germany, India, France and other countries refused to provide troops for the U.S.-led force without a U.N. mandate.

Fox News' Bret Baier and The Associated Press contributed to this report.