As the U.S. second largest metropolis, Los Angeles will be on heightened vigilance on the 9th anniversary of the 9/11 terror attacks, authorities said on Friday.

Saturday is clearly "a day of national significance," said Los Angeles Airport Police Chief George Centeno.

"Airport police will enhance our deployment accordingly through high visibility patrol, directed patrol and use of additional plain- clothes officers," he said.

"Details of such operational deployments, however, will not be made public," he said.

On Tuesday night, a few days in advance of the 9/11 anniversary, security concerns were heightened when an incoming Thai Airways flight received a bomb threat.

The threat prompted authorities to have the plane taxi to a remote part of LAX and remove about 200 passengers and crew. But a bomb squad inspection of the aircraft turned up no evidence of an explosive.

"We can never be too prepared, but since then, coordination among local, state and federal agencies has improved; new technologies have been deployed in our city; and specialized units stand ready to respond to scenarios that were once unthinkable," City Council President Eric Garcetti said of the incoming anniversary.

"The attacks of September 11, 2001, still reverberate today, even across the country here in Los Angeles," said Garcetti.

The Los Angeles Police Department (LAPD) said it has not received any information indicating the threat level will be higher this weekend than it has been any other weekend.

"I won't say it's routine, because nothing is routine," Capt. Mike Downing of the LAPD's Counter-Terrorism and Criminal Intelligence Bureau said of the department's emergency plans.

"We're digging in and are as engaged as we've ever been and as we will continue to be."

He stressed the importance of continued outreach in the community to encourage vigilance.

"There will be a lot of events this weekend, and we will be there," he said.

Some additional concerns have been expressed about security this year given the threat by a Florida pastor to burn copies of the Quran.

Pastor Terry Jones in Florida threatened to burn 1,000 copies of Quran, the Islamic holy books on Saturday's ninth anniversary of 9/11.

Under mounting pressure, Jones said later he was going to cancel the book burning because developers of a proposed Islamic center two blocks from Ground Zero in Manhattan had agreed not to place the center there.

But after those involved with the center denied there was such an agreement, Jones said his event may still go forward unless he could meet with the Moslem imam in charge of the project.

"Anyone who preaches God and the Bible and doing good for human beings and then to advocate what he's advocating ... I think the man's crazy for what he's doing," L.A. City Councilman Dennis Zine said.

"You can't say all Moslems are terrible, all Moslems are evil people. He's the one who's the problem. In a free society you (the pastor) can speak your mind but he's causing a lot of havoc in the meantime."

Zine also said residents should be vigilant to help law enforcement in the fight against terrorism.

"Terrorism -- we know now -- is an ever-present danger," Zine said. "We've become more aware. We've become better prepared with emergency operations."