No one was hurt in the 2 a.m. blast, the police said.
In a phone interview, Emano said there is no cause for alarm, adding that the National Intelligence Coordinating Agency (NICA) is now investigating the incident.
"The explosion could have been caused by a big firecracker or a small bomb and was intended to embarrass me. It was obviously political harassment," he said.
"If it was the handiwork of terrorists, then it was just intended to scare me since it occurred at 2 a.m. and there was no one around," he said.
Emano has been at odds with some members of the city council after they filed charges against him in the Office of the Ombudsman.
Emano laughed off allegations by councilor Zaldy Ocon in a radio interview that the explosion was meant to divert the people’s attention from the mayor’s cases in the Ombudsman and that records were destroyed in the blast.
"It is not true that City Hall records were destroyed in the explosion. What were destroyed were the building’s electrical switches," he said.
Ocon, a radio announcer, has been a critic of Emano even before he (Ocon) was elected to the city council last year.
"The situation is under control but the investigators are still (clueless)," Emano said.
Superintendent Honorio Cervantes, Cagayan de Oro City police chief, said the explosion was plain harassment.