Los Angeles, California (CNN) -- Recent security cutbacks have left the Los Angeles International Airport vulnerable to terrorist attacks, according to a letter from an airport police union calling for a restoration of the security measures.
The letter, released Tuesday, is from Marshall McClain, president of the Los Angeles Airport Peace Officers Association, to Los Angeles Airport Police Chief George Centeno. The letter says that because of cost-cutting reductions in training, the deployment of traffic control officers and security in the central terminal, the airport is "more vulnerable to a terrorist attack than at any time since 9/11."
Gina Marie Lindsey, the executive director of Los Angeles World Airports who is also copied on the letter, said in a statement Tuesday that "there is no evidence to support" McClain's allegations, noting that the airport police budget "has increased annually since 9/11 and, from last fiscal year to this year, it increased nearly $3.4 million."
Lindsey's statement also emphasized the airport's security, noting that "LAX remains one of the safest airports in the world and one of the safest areas in Southern California due to LAWA's continuing commitment to staff, train and equip Airport Police."
Meanwhile, McClain's letter identifies the three most likely attack scenarios as determined by a Rand Corporation study of airport security at LAX in 2004: a large truck bomb, a curbside car bomb and a luggage bomb.
The letter, dated June 8, also calls attention to the lack of permanent checkpoints at the airport's six entrances as recommended by the Rand organization in 2006 "to reduce the risk of car-bomb attacks."
"Not only has the program not advanced beyond the design phase, the random checking of vehicles entering the (Central Terminal Area) has been greatly curtailed in recent months," McClain writes.
Nancy Castles, a spokeswoman for LAX, told CNN Tuesday that the fixed checkpoints recommended by Rand "weren't implementable," saying that because of the short road leading into the airport, traffic would be backlogged into the major thoroughfares surrounding LAX.
Instead, Castles noted, the airport worked in conjunction with engineering students at the University of Southern California to develop a randomized checkpoint system that's determined by computer.
The program determines the number and location of checkpoints on any given day based on the number of officers available to man them, she said.
"Randomization and unpredictability is a key factor in keeping the terrorists unbalanced so they can't size you up and attack you," Castles said. "It is so effective that airports across the United States ... are adopting this method."
McClain, for his part, points out that since 1974, the airport "has been the site of two bombings, two attempted bombings and one gun attack."
"There is no reason to believe LAX is no longer an attractive target," he writes in urging Centeno, Lindsey and other airport and city officials to "review and reverse recent decisions that have significantly reduced LAX's ability to deter an attack."
The letter also requests an "urgent meeting" with Centeno to discuss the security measures, however, as of Tuesday, no meeting had been scheduled, McClain told CNN -- an allegation Castles disputed.
The LAAPOA represents more than 450 airport police officers and fire personnel, according to its website.
LAX is the world's seventh busiest airport in terms of passenger traffic, according to 2009 statistics from the Airports Council International.
CNN's Sarah Aarthun contributed to this report.