An explosive device has gone off outside the home of an employee of the U.S embassy in the Georgian capital, Tbilisi, shattering windows but causing no injuries.

Georgian officials say they are investigating the blast late Friday, but they have given no details.

News media reports say the explosion occurred after three young men passed by the building and threw something into the yard.

Authorities have not identified the embassy employee in question, and embassy officials have issued no comment.

Some information for this report provided by AP.