A suspected letter bomb attack on the UK embassy in Zagreb, Croatia, has left one man with minor injuries.
Sniffer dogs are being used as part of the hunt for the culprits
A device exploded in a post room at about 0630 BST, the UK Foreign Office said, leaving a Croatian worker with slight injuries to the lower leg.
Croatian President Stipe Mesic condemned the incident in his country's capital as a "terrorist attack" and vowed to track down those responsible.
Croatian authorities said it was lucky the incident was not on a bigger scale.
No group has yet said they carried out the attack, which police are investigating.
It comes after several embassies received threatening letters this year.
A Foreign Office spokesman said he was unaware of any threats to the embassy, but said security at the building had been stepped up.
Ambassador Sir John Ramsden attended the embassy in the capital as the investigation got under way.
He confirmed the blast happened in the post room and thanked the Croatian Ministry of the Interior for its help.
"I would also like to thank Prime Minister Sanader and all other Croatian officials that have immediately contacted us with messages of support," he added.
War crimes suspect
Interior minister Ivica Kirin said British citizens in Croatia had no reason to fear for their safety.
The EU postponed entry talks with Croatia in March over the country's failure to co-operate fully with the United Nations war crimes tribunal.
As current EU president, Britain will oversee a reassessment of Croatia's membership bid in the next few weeks.
The application was put on hold in March because Zagreb failed to arrest war crimes suspect General Ante Gotovina, revered as a hero by many Croats.
Croatia's Prime Minister Ivo Sanader told Reuters news agency he believed the incident could be directed against Croatia's efforts to join the EU.
"There are certainly people who want to slow down Croatia's integration into the EU," he is quoted as saying.
"By this I do not mean Eurosceptics, which is a legitimate political position. Whatever the motives, we will not tolerate such acts."