The explosion in downtown Budapest Saturday night was caused by some kind of bomb, not by gas leak, Attila Ladocsi, Hungarian forensic demolition expert, told television channel M1 on Sunday.
It was definitely some kind of bomb, he said, adding that the debris around the shop at the corner of Terez Ring and Kiraly Street clearly showed that a large amount of explosive was behind it.
It is a highly frequented area with many cafes, restaurants, night clubs and hotels, all packed on Saturday night.
Asked if it had been a pipe bomb as alleged by the daily newspaper Nepszabadsag, Ladocsi said the explosion was far more powerful than a pipe bomb, and was definitely a homemade device.
Police have called for eyewitnesses to come forward to help hunt down the bomber who will be charged with attempted murder.
The device went off at around 10:30 p.m.local time (2030 GMT) on Saturday night. It broke neighborhood windows and could be heard miles away.
Two police officers patrolling the area were hurt and hospitalized with undisclosed injuries. They were the only wounded, the police stated.
The police declined to give further information, saying that it was in the interests of the investigation to remain silent.