A suspicious device found in a car in Luton was deemed "not viable" by a bomb disposal team.
Police were called to Brook Street at about 07:20 GMT to reports of concern for a man in a vehicle.
Officers found a suspicious device in the car in Dunstable Road and the explosive ordnance disposal (EOD) team was called, Bedfordshire Police said.
Two men have been arrested for explosives related offences.
A second car was also checked for devices, police said.
The force said one man was arrested at the scene and a second man was arrested shortly afterwards in Brook Street, both on suspicion of offences committed under the explosives act.
Homes and businesses were evacuated and roads closed in the Bury Park area after the device was found and people were advised to avoid the area.
Supt Jaki Whittred said it was a "complex investigation" and officers remained in the area while the force worked to establish the circumstances which led to the device being found.
"I understand that this is concerning for local residents in Luton but I'd like to reassure you that our officers, EOD specialists, and a number of our partner agencies are working closely together to ensure the safety of the public," she said.
"Brook Street and Dunstable Road remain closed as a result of this and I'd like to thank residents and business owners in the vicinity for their patience with this."
One local shop owner, who wanted to remain anonymous, said he had been ordered not to open his business.
"It's a big shock," he said.
"You don't expect to come out in the morning and not open your business."
Around 50 people were evacuated but were later allowed to go home.