UPDATE: Police have given metro the all clear at Flagstaff station and services will resume.
EARLIER: All city loop trains are being diverted straight to Flagstaff station due to an incident.
There are early reports of a man with a gun at Flagstaff station from a member of the public, while others report seeing police on platform 3 and four. Police are yet to comment on the situation.
PTC have confirmed all city loop trains have been suspended with city loop services running direct to Flinders Street - but won't say why.
More to come.