The authorities in Georgia have released a photo of a man wanted over the throwing of a grenade during the visit by US President Bush in May.
Officials have not been able to name the suspect
They also announced a 150,000 lari ($80,000, £45,000) reward for information leading to his capture.
The hand grenade was hurled into the crowd during a speech Mr Bush gave in the Georgian capital Tbilisi.
It was found 30m (100ft) from the stage. It had failed to explode, though the FBI said it was live.
The man who appeared in the photograph released on Monday had dark hair and wore dark glasses.
Interior Minister Vano Merabishvili said officials did not know who the man was, but that he was believed to between 25 and 35 years old, and 175-180cm tall (5ft 9in).
"I am appealing to the mass media for help" he said.
He said the photo was being passed to police and border guards in former Soviet state.
Mr Bush addressed a crowd in a main Tbilisi square on 10 May, during a visit to bolster relations and express support for democracy in the country following its Rose Revolution in 2003.
Georgian President Mikhail Saakashvili was also on the podium, and both men spoke from behind bullet-proof glass.