Police in Croatia have arrested a local worker at the British Embassy in Zagreb over a blast in the mailroom in which he was injured.
Sniffer dogs were used to search the embassy
Damir Rovisan, 28, had confessed to smuggling the device into the embassy, said Interior Minister Ivica Kirin.
Rovisan suffered slight injuries to his lower leg in the blast in the capital at 0630 BST on Monday.
Mr Kirin said the explosion was now thought to be criminal rather than terrorist in nature.
The minister said Rovisan had recently been sentenced to 16 months in prison and had been due to start his sentence earlier in the month.
The suspect had worked at the embassy for four year, Mr Kirin said, but did not reveal whether a motive for the attack had yet been established.
Croatian President Stipe Mesic condemned the incident on Monday as a "terrorist attack" and Prime Minister Ivo Sanader said it could be an attempt to derail the Balkan nation's efforts to join the EU.
But Mr Kirin said: "Damir Rovisan admitted today that he had carried in the explosive and set off the device.
"This indicates that this is not a terrorist act against the British embassy, but an act of an individual coming from criminal circles."