An unidentified injured Israeli tourist is carried in front of Borgas hospital after an explosion 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, 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 Destroyed buses are seen 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, 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 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 Smoke rises into the sky after an explosion 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, 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/ Burgasinfo) BULGARIA OUT