CHICAGO (CBS) — Chicago Police on Sunday said charges were pending against a man arrested in the shooting of a CTA bus driver right downtown the evening before.

As CBS 2 Political Investigator Dana Kozlov reported, this was the latest among numerous violent incidents on Chicago Transit Authority buses or trains – and it is likely to renew the call for more CTA security.

READ MORE: 5 Killed, 39 Wounded In Weekend Shootings Across Chicago

Security has been one of the greatest concerns over the past several months for the Amalgamated Transit Union Local 241, which represents CTA employees.

In the Saturday night incident, police said the bus driver was physically attacked and was then shot in the jaw. The shooting happened at Washington Street and Garland Court around 9 p.m., a short distance west of Michigan Avenue Millennium Park and right outside the Chicago Cultural Center.

Sources told Kozlov the driver was found off the bus.

Exactly what led up to the shooting was still being investigated Sunday. But this came less than two weeks after Curtis Tyler, 30, was charged with attacking someone with a hammer on a CTA Red Line train and was linked to several other similar attacks.

READ MORE: Man Shot, Critically Wounded In Car Downtown

This latest incident also came about three weeks after a man was shot and killed on a Red Line train at the Garfield stop during the afternoon rush.

For months, CBS 2 has been reporting on the call for increased security from the union representing CTA drivers. One thing for which they have called is hiring armed security guards.

“We will push and help the authorities identify the routes that we deem troublesome,” Amalgamated Transit Union 240 President Keith Hill said on June 30.

CBS 2 has reached out to see if Hill had more to say about security after this latest incident.

“This incident is absolutely unacceptable,” said CTA President Dorval R. Carter, Jr. on the shooting. “There is no reason the men and women who serve the city should be subject to any kind of attack. These are dedicated public servants who should be able to perform their duties in a safe environment free from this kind of violence.”

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The driver shot Saturday night remained in serious condition as of the latest report.