A hand grenade was found at a Finnish Red Cross (FRC) shop in Oulu, northern Finland, on Saturday.
The local police department said on Twitter that the grenade was found among donated items dropped off for sale at the Kontti charity thrift shop.
"The building has been evacuated and police are guarding the area. The Finnish Defence Forces have begun preparations to remove the hand grenade," Oulu Police tweeted around midday.
Explosive ordnance disposal technicians were on their way from the Kainuu Brigade in Kajaani, nearly 200km away. Local newspaper Kaleva reported on Saturday afternoon that the device had not yet been defused or removed.
Oulu Police Commissioner Juha Niemelä told Yle that it was not immediately clear whether the grenade was functional or even genuine.
"But I'd say that it looks like a real hand grenade," Niemelä said.
"The shop was closed due to a donated item that we received, which is probably a wartime souvenir or something like that," said Leevi Heimonen, director of the FRC's 12 Kontti shops. He told Kaleva that it was not clear when the item had been dropped off, "but probably not today".