The driver of a bus which crashed into several vehicles in Glasgow city centre, leaving two men injured, has been suspended as an investigation is carried out.

Reports have suggested the First bus was a runaway vehicle when it crashed into a car and other buses on Renfield Street.

An eyewitness also claimed the driver went into a newsagent before the vehicle rolled away.

The crash took place at 3.45pm on Monday and the busy road was closed for several hours.

Two men were injured in the incident, including a pedestrian who was hit by a car which was forced forward by the bus.

Witness Arran Watkins said he saw the driver get out the vehicle to visit a newsagents and chase after his bus when it started to roll.

He said: "The driver ran into a newsagents and the bus started rolling down the hill.

"He chased after it but the bus hit a blue Renault Twingo which was then smashed forward and hit a pedestrian. He was about 18 years old.

"Another pedestrian gave him first aid and then the emergency services turned up.

"The boy was lying on the ground and he was still conscious from what I could see."

The First bus then went on to hit a single-decker bus and was left badly damaged in the front passenger door area.

Paul McNamee, editor of the Big Issue magazine, also witnessed the crash.

He told STV News: "I just heard a bang, looked around and saw a double-decker bus coming down Renfield Street. There didn't appear to be anyone in it."

The number 60 then collided with another bus, which caused it to hit other vehicles.

He added: "It was just lucky it hit a stationary bus, had it gone through St Vincent Street it would have been much more serious."

The passengers of the buses were then taken off the vehicles, he said.

Another witness, who did not with to be named, told STV News he saw the bus driver running after his vehicle looking panicked.

He said: "I was just walking up Renfield Street, I saw the driver running at full speed looking panicky. "I looked down the road and I saw the bus itself going straight down, picking up speed, and that's when it hit the first car.

"When it hit the car it hit a passerby, he was lying on the road.

"Then the bus went further down and it hit another bus, there was a huge impact."

One of the buses involved was a service headed for Queen Elizabeth University Hospital in Glasgow.

A spokesman for First Glasgow said: "We can confirm that a First Glasgow vehicle was involved in an incident on Renfield Street this afternoon.

"It's too early to speculate on the cause of the incident, however, we've launched an immediate investigation and will work closely with the emergency authorities to determine exactly what happened.

"Our thoughts at this time are with the two men who were injured as a result of the incident."

Regarding the suspended driver, a spokesperson said: "As per our procedures the driver concerned has has been relieved of his duties while we undertake a detailed investigation."

Police Scotland said two men were taken to Glasgow Royal Infirmary after being injured. Officers appealed for anyone with information to contact them via 101.

It is understood those who were injured were not seriously hurt.

Glasgow City Council has said the surrounding roads are very busy and should be avoided if possible.