Taxi driver Shawinder Brar was severely injured when he was attacked by three people and beaten with a metal bar. (CBC)

Two teens have been charged in connection with a string of violent assaults and robberies of Calgary taxi drivers.

Police said Thursday that they arrested two males at separate northeast locations Wednesday, and are looking for two others.

A 15-year-old has been charged with six counts of robbery while a 16-year-old faces seven counts of robbery. The Youth Criminal Justice Act prohibits disclosing their names.

Seven similar incidents in which drivers were called to pick up customers in the northeast neighbourhoods of Falconridge and Abbeydale have been reported to police since Feb. 14.

In each case, once the taxi arrived, three men would ambush the driver.

"The motivation obviously is to get the money, the robbery. There is a drug element involved in this," acting Insp. Steve Lorne said. "They were not involved in a gang."

He said the arrests came as a result of both a public tip and an undercover police operation.

'Just because we don't announce an arrest the very next day, doesn't mean we're not working on the file.'— Chief Rick Hanson, Calgary Police Service

Police are looking to arrest two other male teens who have been identified.

"It'd be just a matter of time before we do pick them up," Lorne said.

As CBC News first reported, five drivers were attacked with various weapons. In four of the cases, they were robbed. Upset cabbies flooded a public meeting last week to demand Calgary police do more about the attacks.

Chief Rick Hanson reassured the public Thursday that the cases were a priority for the force.

"Just because we don't announce an arrest the very next day, doesn't mean we're not working on the file," he said at a news conference.

"[Investigators] recognized right from the onset how this was being perceived in the community, the concern that existed in the community, the sense of fear. These officers put in countless hours on the job, on duty and of their own time and overtime to bring this file to successful conclusion."

As part of their investigation, police searched two locations and seized a handgun and a pellet gun, they said.

One of the injured drivers, Monmohan Grewal, said Thursday that he was relieved to hear of the arrests, but he hopes the suspects will not be severely punished.

"I don't want anybody to get into trouble. That's what I got taught by my father," he told CBC News. "We don't believe in these things. We believe in more education that these people can learn."