The Canadian Press, File / The American embassy in Ottawa: Subject of an al-Qaeda attack plot?

OTTAWA - A network of al-Qaeda agents was rounded up before it could carry out a plot to attack the American Embassy in Ottawa, U.S. intelligence sources say.

The Central Intelligence Agency was alerted to the al-Qaeda conspiracy by Syria's intelligence service, which has been co-operating with Washington since the Sept. 11 terrorist attacks, sources say.

Flynt Leverett, a former CIA analyst who until recently served at the U.S. National Security Council, confirmed Thursday that a suspected plot against an American target in Ottawa was averted, but would not provide further details.

However, sources told CanWest News Service that al-Qaeda planned to attack the U.S. Embassy, aiming at least to kill the Marine guards who form the frontline of defence at the heavily guarded embassy in the capital's downtown core.

An official at the U.S. Embassy had no comment when asked about the aborted attack while CSIS spokesman Phil Gibson said: "We can't talk about operations for reasons of national security."

RCMP Insp. Andre Guertin said the force has no knowledge of any terrorist plot to assault the embassy.

Sources would not give a time frame for the attack nor say whether it involved a bomb, but credited Syrian intelligence for alerting the CIA which passed on the information to Canadian authorities.

"We were able basically to round up a network that was going to carry out the plot," one high-level source said.

The revelation about an al-Qaeda plot at an American target in Ottawa was first reported by investigative journalist Seymour Hersh in this week's New Yorker.

"What Hersh had in the article, I can confirm is accurate, but I can't really go further than that," said Leverett, now a fellow at the Saban Centre at the Washington-based Brookings Institute. "I can't talk about the details of that."

Leverett said Syria provided Washington with first-rate intelligence about future al-Qaeda plans, including the Ottawa conspiracy and a plot to fly a glider loaded with explosives into the U.S. Navy's 5th fleet headquarters in Bahrain.

"The reports we got exceeded (CIA) expectations, both in quantity and quality, and several of them turned out be

actionable. We actually could do things to stop operations from going down on the basis of what the Syrians told us," Leverett said.

"We could break up networks. Bad guys got arrested. It was useful stuff."

Ahmad Arnous, the Syrian ambassador to Canada, said Thursday he did not have personal knowledge of the al-Qaeda intrigue, but confirmed Syrian intelligence has provided useful information to the CIA and CSIS.

Arnous said Syria even shared classified information with the CIA and CSIS on Maher Arar, a Syrian-born Canadian citizen who U.S. authorities say has ties to al-Qaeda.

Arar, a 32-year-old Ottawa engineer who was the target of a joint Canada-U.S. investigation, is now in a Syrian prison because of alleged links to terrorism.

Sources say Arar was tracked when he left Canada last year for a vacation to Tunisia. On his return home, he was arrested Sept. 26 by U.S. immigration authorities while changing flights at New York's Kennedy Airport and deported to Syria on Oct. 8, even though he was carrying a Canadian passport.

"There is some kind of co-operation between all countries friendly with Syria, including Canada because even on Mr. Arar there was a communication between the security people in Canada and Syrian anti-terrorism people," Arnous said.

Arar was first sent to Jordan for 10 days where the CIA has a special interrogation site for al-Qaeda agents.

In April, U.S. ambassador to Canada Paul Cellucci told a private audience

that Arar was under surveillance long before his arrest and deportation to Damascus.

"Mr. Arar is very well known to Canadian law enforcement. They understand our handling of the case. They wouldn't be happy to see him come back to Canada," Cellucci said.

Last month, Prime Minister Jean Chretien wrote to Arar's wife, Monia Mazigh, promising to fight for the return of her husband to Canada, although Foreign Affairs acknowledges they have not been able to see Arar since last April.

But a U.S. source said the Canadian government "knows much more about Arar than they are telling Canadians," saying the RCMP quietly asked the U.S. government to arrest Arar in New York and deport him. "Arar had been monitored for a long time. Canadian authorities knew about him long in advance before his arrest. He had been in Afghanistan with al-Qaeda."

Arar's wife denies her husband was ever in Afghanistan and insists he is not linked to al-Qaeda or any other terrorist group.

The Syrians also arrested another Ottawa man, Abdullah Almalki, last summer when he was travelling in Syria. Almalki remains in a Syrian prison, but little is known about him or the arrest.

According to the New Yorker, the Syrians compiled hundreds of files on al-Qaeda and penetrated al-Qaeda cells throughout the Middle East and in the Arab exile community.

9/11 attack was preventable, says a U.S. government report on terrorism, see page A4.