VANCOUVER - The Vancouver 2010 Olympics went off with only slight security glitches, but diplomatic cables released Thursday show police were on alert for much, much worse.

A U.S. citizen was deported after Canadian border guards found an inert hand grenade and a typed paper outlining a scenario for paragliding into the opening ceremonies of the Winter Olympics, says one of the cables released Thursday among a batch dumped by Wikileaks.

The U.S. consul in Vancouver reported in one of his daily dispatches that the man planned to launch himself from Whistler and fly towards Vancouver "with the goal of gaining notoriety."

An FBI interview later determined the man was emotionally disturbed and had no ties to domestic militia groups.

Two days after the opening ceremonies, on Feb. 14, the consul reported that Vancouver police had been notified after an inmate in a Florida jail had a conversation with "a prisoner of Arabic origin" regarding a possible terrorist attack on Feb. 20.

According to the information obtained by the FBI, the attack involved an aircraft being flown into the main area of the Olympics in Vancouver.

But the FBI had determined that no one matching the alleged Arab inmate was currently in jail.

"This threat is considered non-credible," stated the cable.

The same cable also noted that someone was detained after attempting to enter the International Olympic Committee's presidential box inside B.C. Place during the opening ceremonies.

The person had used fake credentials, but wasn't a known activist and didn't appear to have a malicious intent.

The cable said the person's intentions were never determined.

On Feb. 18, 2010, authorities received a phone call telling them to "please check your Phoenix to Vancouver flights."

The caller hung up and the nature and credibility of the call were "undetermined," but the information was "being addressed as a potential threat."

U.S. law enforcement agencies in Phoenix and Charlotte investigated the call, along with the FBI and inspections and screening activities were stepped up at the Phoenix airport, the cable said.

The next day, the FBI received an anonymous letter alleging an unspecified Olympic attack by an "alleged international terrorist of Fijian descent currently living in Canada."

The letter said she and her sister "are planning to do a big one in the Winter Olympics."

The cable went on to say that the alleged terrorist had returned to Fiji "to obtain additional training and would attempt to re-enter Canada via Los Angeles between Jan. 1 and 30, 2010."

"The letter appears to have been mailed from Canada. The RCMP is aware of and investigating the information."

The diplomatic cables issued daily during the Games make it clear security officials were keeping a very close eye on protest activity, including the vandalism that ripped through the city's downtown the morning after the opening ceremonies. At one point, a cable makes specific reference to 171 people expected to turn up at a demonstration.

Some security instances were reported during the Olympics.

A suspicious package obliterated by a police water cannon disrupted commuter traffic across a Vancouver waterway. The package turned out to be fishing gear.

The highest-profile incident prompted a tweak to the $900-million security plan after a man managed to get into the Olympic opening ceremonies and come within a few metres of U.S. Vice-President Joe Biden. Authorities determined the man was "infatuated" with Biden, and had no malicious intent.