Bulgarian policeman is seen in front of destroyed buses at Burgas Airport, outside the Black Sea city of Burgas, Bulgaria, some 400 kilometers (250 miles) east of the capital, Sofia, Wednesday, July 18, 2012. A bus carrying young Israeli tourists in a Bulgarian resort exploded Wednesday, at least killing three people and wounding at least 20, police said. Witnesses told Israeli media that the huge blast occurred soon after someone boarded the vehicle. (AP Photo/ Bulphoto Agency) BULGARIA OUT

Map locates resort attack on the Black Sea

A tourist agency employee reacts as he passes by Bulgarian policemen shortly after a bomb attack against Israeli tourists near Burgas airport, outside the Black Sea city of Burgas, Bulgaria, some 400 kilometers (250 miles) east of the capital, Sofia, Wednesday, July 18, 2012. A bus carrying Israeli tourists in the Bulgarian resort city of Bourgas exploded Wednesday killing at least three people and wounding more than 20 others, police said. (AP Photo/ Impact press Group)

A family waits near Burgas airport, shortly after a bomb attack against a bus with Israeli tourists, outside the Black Sea city of Burgas, Bulgaria, some 400 kilometers (250 miles) east of the capital, Sofia, Wednesday, July 18, 2012. A bus carrying Israeli tourists in the Bulgarian resort city of Burgas exploded Wednesday killing at least three people and wounding more than 20 others, police said. (AP Photo/ Impact press Group)

A Bulgarian policeman with a sniffer dog checks for explosives by parked buses at Burgas airport, outside the Black Sea city of Burgas, Bulgaria, some 400 kilometers (250 miles) east of the capital, Sofia, Wednesday, July 18, 2012. A bus carrying Israeli tourists in the Bulgarian resort city of Burgas exploded Wednesday killing at least three people and wounding more than 20 others, police said. (AP Photo/ Impact press Group)

Passengers sit beside the road shortly after an explosion near Burgas airport, outside the Black Sea city of Burgas, Bulgaria, some 400 kilometers (250 miles) east of the capital, Sofia, Wednesday, July 18, 2012. A bus carrying young Israeli tourists in a Bulgarian resort exploded Wednesday, killing three people and wounding at least 20, police said. Witnesses told Israeli media that the huge blast occurred soon after someone boarded the vehicle. (AP Photo/ Impact press Group)

Unidentified Israeli tourist is helped as she arrives to Bourgas hospital after a bus carrying Israeli tourists in the Bulgarian resort city of Bourgas exploded Wednesday, July 18, 2012, killing at least three people and wounding more than 20 others, police said. Israel says it is holding Iran responsible for the explosion on a bus carrying Israeli youths today at a resort in the Black Sea city of Burgas, some 400 kilometers (250 miles) east of the capital, Sofia. (AP Photo/ Bulphoto Agency) BULGARIA OUT

Unidentified Israeli tourist is helped as she arrives to Bourgas hospital after a bus carrying Israeli tourists in the Bulgarian resort city of Bourgas exploded Wednesday, July 18, 2012, killing at least three people and wounding more than 20 others, police said. Israel says it is holding Iran responsible for the explosion on a bus carrying Israeli youths today at a resort in the Black Sea city of Burgas, some 400 kilometers (250 miles) east of the capital, Sofia. (AP Photo/ Bulphoto Agency) BULGARIA OUT

Israeli military and medical personnel talk in front of a hospital in the city of Burgas, Bulgaria, Thursday, July 19, 2012. A daytime bombing that killed eight people and injured dozens on a bus full of Israeli tourists was most likely a suicide attack, Bulgaria's interior minister said Thursday. He said the suspected attacker was carrying a Michigan driver's license that was being sent to the FBI for authentication. (AP Photo/Impact Press Group)

This image taken from CCTV provided by the Bulgarian Interior Ministry who claim it shows the unidentified bomber, centre, with long hair and wearing a baseball cap, at Burgas Airport on Wednesday, July 18, 2012. The brazen daytime bombing that killed seven people and injured dozens on a bus full of Israeli tourists was most likely a suicide attack, Bulgarian officials said Thursday. Israel stood by its claim that Iranian-backed Hezbollah was responsible and vowed to hit back. The identity of the suspected bomber was still unknown but a Michigan driving license that he carried was a fake, Bulgarian Prime Minister Boiko Borisov said. (AP Photo/Bulgarian Interior Ministry)

This image taken from CCTV provided by the Bulgarian Interior Ministry who claim it shows the unidentified bomber, centre, with long hair and wearing a baseball cap, at Burgas Airport on Wednesday, July 18, 2012. The brazen daytime bombing that killed seven people and injured dozens on a bus full of Israeli tourists was most likely a suicide attack, Bulgarian officials said Thursday. Israel stood by its claim that Iranian-backed Hezbollah was responsible and vowed to hit back. The identity of the suspected bomber was still unknown but a Michigan driving license that he carried was a fake, Bulgarian Prime Minister Boiko Borisov said. (AP Photo/Bulgarian Interior Ministry)

RETRANSMISSION FOR ALTERNATIVE CROP This image taken from CCTV provided by the Bulgarian Interior Ministry Thursday July 19, 2012 who claim it shows the unidentified bomber, center, with long hair and wearing a baseball cap, at Burgas Airport in Burgas, Bulgaria on Wednesday, July 18, 2012. The brazen daytime bombing that killed seven people and injured dozens on a bus full of Israeli tourists was most likely a suicide attack, Bulgarian officials said Thursday. Israel stood by its claim that Iranian-backed Hezbollah was responsible and vowed to hit back. The identity of the suspected bomber was still unknown but a Michigan driving license that he carried was a fake, Bulgarian Prime Minister Boiko Borisov said. (AP Photo/Bulgarian Interior Ministry)

RETRANSMISSION FOR ALTERNATIVE CROP This image taken from CCTV provided by the Bulgarian Interior Ministry Thursday July 19, 2012 who claim it shows the unidentified bomber, center, with long hair and wearing a baseball cap, at Burgas Airport in Burgas, Bulgaria on Wednesday, July 18, 2012. The brazen daytime bombing that killed seven people and injured dozens on a bus full of Israeli tourists was most likely a suicide attack, Bulgarian officials said Thursday. Israel stood by its claim that Iranian-backed Hezbollah was responsible and vowed to hit back. The identity of the suspected bomber was still unknown but a Michigan driving license that he carried was a fake, Bulgarian Prime Minister Boiko Borisov said. (AP Photo/Bulgarian Interior Ministry)