PODGORICA, Reuters, February 21, 2018 – An unknown person threw an explosive device, probably a hand grenade, at the United States embassy building in Podgorica, the capital of Montenegro, before blowing himself up, the government said on Thursday.

Messaging in English on its official Twitter account, the government said that half an hour after midnight (1130 GMT), “An unknown person committed suicide with an explosive device.”

It added, “Immediately before, that person threw an explosive device from the intersection near the Sport Center into the U.S. embassy compound.”

It said, “Most probably, the device was a hand grenade,” adding that police investigation and identification were underway.

“Immediately before, that person threw an explosive device from the intersection near the Sport Center into the U.S. embassy compound.”

The device was most probably a hand grenade, it said. Police were investigating and trying to establish the person’s identification.

The embassy was closed for issuing visas on Thursday and it warned U.S. citizens to stay away until further notice.

“The U.S. embassy in Podgorica advises U.S. citizens there is an active security situation at the U.S. embassy in Podgorica,” it said on its website.

Montenegro is the smallest of all former Yugoslav republics and became the 29th country to join NATO last