GLASGOW'S Subway has been brought to a standstill due to a "casualty on the tracks".

British Transport Police has said it is responding to the incident alongside the ambulance service after the alarm was raised at 3.50pm.

It is understood the casualty is being seen to at Kelvinbridge.  

Glasgow Subway said it was a "passenger-related incident".

It said on social media: "Both circles currently suspended due to a passenger related incident. We'll update when services back up and running."

One onlooker told social media:  "Was at a station - Kelvinbridge I think, When the girls opposite me freaked out and the train coming the other way came to a sudden stop.

"The girls think they heard someone shout help. And there were people kneeling on the platform looking down at the tracks through the train."

It comes just a few hours after British Transport Police warned that the subway would be busy, with likely queuing at Buchanan Street and Partick from 6pm because of Rangers' sell out Europa League tie against Porto at Ibrox.

Glasgow Subway said at just after 5pm that all services had begun running again.

"Thank you for your patience and apologies for the inconvenience," Glasgow Subway tweeted.

UPDATE 4.36PM:  The Outer Circle has begun resuming services.

UPDATE 5.09PM:  The Inner Circle has begun resuming services.