PODGORICA, Montenegro (AP) — Montenegro says an attacker threw a grenade at the U.S. Embassy in the capital of the Balkan state then killed himself with another explosive device.

The area was sealed off by police, and the embassy warned Americans to avoid the area because of "an active security situation."

Montenegro's government said the unknown assailant hurled the grenade into the embassy compound around midnight (1100 GMT) and then killed himself with another explosive device. No one else was hurt and there was no major damage.

Montenegro borders the Adriatic Sea in southeastern Europe and its capital is Podgorica. It joined NATO last year.

The U.S. established diplomatic ties with the tiny Balkan state in 2006 after it split from much larger Serbia.