SAN FRANCISCO - A 17-year-old teenager shocked his fellow passengers after he threw open a plane's emergency door and slid down a wing to the ground on Tuesday (Aug 1).

The incident occurred just minutes after a Copa Airlines plane from Panama City touched down in San Francisco, the BBC reported.

Nearby construction workers confronted him and he was detained until police arrived.

Eyewitnesses said the teen, a US citizen whose name was not disclosed, appeared fidgety and anxious throughout the seven-hour flight.

He had already popped open the emergency door, slid down the plane's wing onto the tarmac and started running before passengers realised the door had been opened.

"It was as if he was like flying out, like it was really fast," passenger Sophia Gibson told San Jose television station KNTV.

Another passenger, 11-year-old Andrea Sepulveda Guzman, said everyone started to scream when he began running.

The teen's motives were not clear, although a police spokesman told ABC News on Wednesday he had been taken for treatment and will not be charged by local authorities.

Copa Airlines, the flag carrier of Panama, confirmed in a statement that the teen had been sitting in an exit row during the flight, but stressed that its crew had followed Federal Aviation Administration rules that required passengers seated there to be at least 15.

It added that exit doors over a plane's wings are intended to be opened by passengers at lower altitudes to facilitate an evacuation in case of emergencies.

A crew member closed the emergency door and the plane taxied to its gate where the remaining passengers alighted without further incident.

No other flights were affected, according to a San Francisco Airport spokesman.