Karoly Papp described the incident as a criminal case of attempted homicide, adding there was no sign that the attack had been carried out by a foreign militant organization, but without ruling it out explicitly.
"We consider this attack occurred against the entire Hungarian police. Someone tried to execute my officers," Papp told a news conference.
He said the attack was clearly directed at police, who were known to patrol the area, on one of the busiest thoroughfares in central Budapest, on a September 24 night. The device was detonated shortly after 10:30 p.m..
It was not immediately clear why police would be the target.
Both the officers needed surgery, with a female officer in a critical condition on September 25 and her male colleague stable.
Police have identified a suspect who was at the scene before the blast and asked for citizens' help to find him. Papp gave a description of the suspect, who he said was a 20-25 year-old male in blue jeans and a hat.
He gave no details on the suspect's nationality.
There was confusion about the cause of the blast on September 24 night, with initial reports suggesting it was a gas explosion.
Police cordoned off a wide area around the Oktogon square and told residents to leave buildings nearest the blast, local media reported. The normally busy intersection was packed with witnesses, including tourists.
Images in local media showed a ruined doorway. Nearby windows and cars were damaged in the blast, witnesses said.
