Although the 70-year-old leader survived the attack in the capital Tbilisi, in which his armoured motorcade came under a 10-minute burst of grenade and machine-gun fire, the incident has underscored the volatility of the small former Soviet republic.
Mr Shevardnadze, speaking on television shortly afterwards, said it was a miracle he was still alive and he urged his compatriots to stay calm.
The former Soviet foreign minister said the attack was "very strong" and he likened it to an assassination attempt in 1995 from which he escaped with cuts.
"This is a second attempt not only to blow up the president but to blow up Georgia as well," said Mr Shevardnadze, who looked tired and gloomy and was flanked by his visibly shaken wife.
"An evil spirit is in the air which dreams of turning everything upside down in this country in order to bring back the era of gangs and armed groups.
"It must be a miracle to survive twice. And I don't mention other cases. Miracles happen only by the will of the Lord. The Lord knows I spare no effort for the good of my country and the people and He saves me in such grave situations," he said.
The former Georgian Communist Party chief said Tbilisi had been sealed and measures taken to ensure order following the attack late on Monday night, in which one bodyguard and one attacker were killed in a heavy exchange of fire.
"We will not allow chaos and instability ... I appeal to everybody to remain calm," said Mr Shevardnadze.
-- Phil Reeves, Moscow