An unidentified attacker threw an explosive device at the United States embassy building in Podgorica, the capital of Montenegro, at 12.30 am (around 5 am Indian Standard Time. Iimmediately after that the attacker killed himself with another explosive device, the government of Montenegro said in a statement. No casualties were reported.

The police said that the device was “most likely a hand grenade” and that they were trying to ascertain the attacker’s identity. The local media reports said that a Serbian-born local resident is the prime suspect, but the authorities did not confirm this, BBC reported.

“We are grateful for the close cooperation with our partner and ally, the government of Montenegro, and we thank the Montenegrin Police for their ongoing professional support with the investigation of today’s incident,” the embassy said in a tweet.

The government of the Balkan nation condemned the incident. “This will not and cannot undermine the high level of safety and security of diplomatic missions or overall security situation in Montenegro,” it said in a statement.