BOGOTA, Colombia — A homemade bomb exploded near Bogota's bullring on Sunday, injuring two dozen police officers and two civilians, Colombian authorities said.

The explosive device, which shattered windows in nearby apartment buildings, appeared to have been left in a sewer outside a new youth hostel popular with foreign backpackers. It was detonated just a few hours before a scheduled bullfight as police in riot gear were gathering ahead of a demonstration by animal rights activists.

Authorities did not give a motive for the blast and said they had no evidence it had anything to do with the resumption of bullfighting at the ring. Some local media speculated the bomb might have been placed by members of the National Liberation Army, the country's second-largest rebel movement, which in recent weeks has carried out small attacks on police targets.

Mayor Enrique Penalosa initially said on Twitter that a police officer was killed. But as the blast scene was controlled, he deleted the tweet and an official police statement said that 26 people had suffered shrapnel and blast injuries, all but two of them officers. All the wounded were taken to three nearby hospitals.

"The terrorists won't intimidate us," Penalosa said, adding that the bullfight would take place as planned despite the incident. "We are going to do all that's necessary to capture them."

Juan David Gonzalez, part owner of El Pit youth hostel, said his two dozen guests were shaken by the blast but none was injured.

"We were all inside having breakfast when we heard the blast. Everyone was in shock but luckily nobody inside was hurt," Gonzalez told The Associated Press.

A video taken at the time of the explosion and broadcast on local TV shows a cloud of debris knocking down a phone cabling box and quickly engulfing a busy street corner as cars and pedestrians move by

Last month, police fired tear gas and arrested dozens of young demonstrators as mobs attacked spectators attending the first bullfight in the capital in four years. But bullfights since then have gone off without a hitch and Sunday's spectacle at Bogota's 1930s-era brick bull ring was the last of the two-month season.

Bogota's previous leftist mayor outlawed bullfighting in 2012. But the constitutional court later overturned the ban, ruling that it was part of Colombia's cultural heritage and could not be blocked.