Georgian President Mikhail Saakashvili said he was handing the Russians over to visiting Belgian Foreign Minister Karel De Gucht, who holds the rotating chairmanship of the Organization for Security and Cooperation in Europe, or OSCE.

But the president also stressed that in terms of the accusations, they have a very well-founded case.

"It is a very solid case of espionage, subversion and trying to destabilize my country."

Saakashvili said although his country wanted good relations and dialogue with Russia, the message was "enough is enough".

In the role as mediator, De Gucht called on both sides to maintain peace.

"I believe that the basic principles of the international law should be respected and I call on both sides to abstain from future provocations and threats of force."

Before handing the four Russians over to the OSCE, Georgian prosecutors reaffirmed the spying accusations against them and barred them from re-entering Georgia.

The arrests last week infuriated Russia, which has put its troops in Georgia on high alert, recalled its ambassador and evacuated its citizens.