A teenager has been arrested on suspicion of possessing an explosive material near High Wycombe railway station.
Police and a bomb squad were called to the scene on Tuesday after a member of public reported concerns about a resident in the area.
Officers attended an address in Amersham Hill and detained a 19-year-old man who remained in custody on Tuesday afternoon.
He was suspected of possessing an explosive material for an unlawful purpose, Thames Valley Police said.
Trains running through High Wycombe ground to halt for about half an hour as the area outside the station was closed off while officers responded to the incident.
Chiltern Railways warned that services calling at the station may be cancelled or delayed for up to an hour following the disruption.
The Explosive Ordnance Disposal (EOD) unit was called and remained at the scene on Tuesday afternoon, Thames Valley Police said.
Motorists and pedestrians were being advised by the force to avoid the area.
Superintendent Emma Burroughs, Policing Commander for South Buckinghamshire, said: “I would like to reassure residents and visitors to High Wycombe that Thames Valley Police and the Explosive Ordnance Disposal unit are at the scene and managing the incident.
“If you are in Amersham Hill and have any concerns or questions, please speak to a police officer, who will support you.
“We would like to thank the public for their cooperation and patience while we respond to this incident. Your support is very much appreciated.
“We will provide further updates when we have them.”