Andy Trigg
BBC News, Buckinghamshire
Laura Foster/BBC
Officers said they did not believe there was further risk to the public "at this time"
Police have shot a man dead outside a railway station after reports he was carrying a firearm.
Officers, who were called to Milton Keynes Central Station at 12:55 BST, said they challenged the man before shots were fired at the suspect.
A man who was nearby said he heard a "very loud" shot and then saw armed officers giving medial assistance to the man on the ground.
A Thames Valley Police (TVP) spokesperson said "life-saving actions were immediately taken" but that he was pronounced dead at 13:44 BST.
"There is not believed to be any further risk to the public at this time," the spokesperson added.
The Independent Office for Police Conduct (IOPC) said it sent investigators to the railway station after being notified by TVP.
James Grant/BBC
Co-Op store worker Barentina Corredor said the incident was "quite shocking"
Hever Marin said he was on a phone call in the station building when he heard the "very loud" shot.
"So we went to out to see and the next thing we see was two armed cops trying to get some medical equipment to resuscitate the guy," he told the BBC.
"They tried for at least 10 minutes. But the guy wasn't reacting."
A picture, seen by the BBC, shows armed police providing medical aid to a man who is lying on the pavement close to the Pret A Manger cafe.
Mr Marin continued: "It was very distressing because, we were just here... and any loose bullets could have impacted us.
"It's very shocking to think how close we were to it."
Co-Op store worker Barentina Corredor said when she heard the noise she "thought we had to find a place where we could hide - I was scared".
"They were trying so hard on CPR - it was quite shocking to be honest," she recalled.
Colin Mackay/BBC
An IOPC spokesperson said it would review the actions and decisions made by officers
TVP is leading on the investigation and British Transport Police said its officers were at the scene giving assistance.
Shazna Muzammil, a councillor and Conservative group leader at Milton Keynes City Council, said she was "deeply shocked" by what had happened.
"Our thoughts are with all those there and affected by it," she posted on X.
"Very thankful to the police and emergency services for their swift response in keeping everyone safe."
Rail operator London Northwestern Railway said train services were unaffected.
However, it warned of reduced access to the front of the station.
A police cordon and a huge presence of officers could be seen outside the main entrance.
An IOPC spokesperson said it would "independently investigate all of the circumstances" including "the actions and decisions taken by the police".
The police watchdog added: "It is in its very early stages and no further information is available at this time."