Security calls on Edmonton's buses and LRT system have increased by 20 per cent over the past three years, officials said Thursday.

The 24 specially trained security officers who patrol the system, along with six supervisors, deal with everything from minor problems like people drinking alcohol in the open, to thefts and assaults.

"We have about 3,500 [calls] in 2004 for the full year and 4,200 in 2007," Glenn Dennis, Edmonton Transit's security operations coordinator, told CBC News.

Officials with Edmonton Transit say they saw a 20-per cent increase in calls for their security staff between 2004 and 2007. (CBC)

On Tuesday, a 13-year-old girl was lured from the Belvedere LRT station in northeast Edmonton by two men who sexually assaulted her at knife-point in a nearby apartment.

Some other transit users said they've also seen an increase in violence.

"A guy was just standing there at the bus stop and people ran over and started hitting him until he bled from the mouth and the face and everywhere," said Zachary Aikman, 17, describing an attack he witnessed last week at the West Edmonton Mall transit centre.

"If those people are starting fights in the day, what could happen at night? There should be more protection here."

Transit managers have asked Edmonton city council for money to hire an additional 12 security officers, bringing the number to 36.

But in the meantime, they have begun using a computer program to maximize their effectiveness. The program analyzes security calls and predicts where future problems might occur.

"We're seven or eight times more likely to encounter what we should be going to by having this model rather than random deployments or just traveling the line," said Dennis.

That computer program would be even more effective, Dennis said, if they have more "feet" on the street.

Last year, Edmonton city council rejected a request for more transit security staff. Officials are hoping they will get a more positive response in this fall's budget.