A man has been detained by police after a bomb scare shut down trains in part of Melbourne's city loop on Saturday.
Trains, which have since resumed, bypassed Melbourne Central station and people were evacuated due to a police operation in response to bomb fears.
Twitter user Linton Wood said a man had climbed onto a moving train and left a bag on its roof.
Ed Brunetti said an announcement at Parliament indicated there were 'unauthorised people' in the city loop tunnel.
Bomb scare at parliament station as a young man climbed onto the moving train and left a bag @theage @theheraldsun pic.twitter.com/Ine484wdke
— Linton Wood (@Unizein) July 23, 2016
@metrotrains what's going on at Melb Central? Was told to evacuate the station
— M a r i a (@bluemint) July 23, 2016
Police operation in the city loop at Melbourne Central. Train on one platform with no lights on. Somethings suss. pic.twitter.com/r2Qx0IEcMj
— Chris Young (@ChrisJamesYoung) July 23, 2016
Victoria Police spokesman Leading Senior Constable Paul Turner said safety checks were conducted at Melbourne Central at 2.20pm.
"Platforms 1 and 2 were evacuated as a precaution," he said.
"The area's been deemed safe. Police have cleared it.
"No injuries have been reported.
"The station's reopened and a 21-year-old man is in custody currently assisting with inquiries."
The man was arrested on outstanding warrants and new charges had not been laid as Saturday night.