Peterborough's Great Eastern Run has been cancelled due to a 'police incident.'
Race organisers and police have tweeted it was cancelled because of a reports of a man acting suspiciously close to the route- on Alexandra Road in Peterborough.
The race was stopped not long after the first runners taking part in a fun run, set off.
Organisers have apologised to everyone taking part or watching the event.
Around 4,000 people were taking part in the half marathon- in one of the biggest events in the city's calendar.