AKIPRESS.COM - Police hunted for a second day on Friday for suspects in the shooting of two police officers at a protest rally in Ferguson, Missouri, after U.S. President Barack Obama said those responsible must be brought to justice, reports Reuters.

The officers were shot and wounded during a demonstration in the St. Louis suburb shortly after midnight on Thursday morning, driving up tensions in a community that has become the center of an intense nationwide debate over race and policing.

Investigators scoured streets near the scene of the shooting for clues and several people were brought in for questioning. They were all later released and there have been no arrests, police said.

The shooting happened just hours after Ferguson's police chief resigned following a U.S. Justice Department report that said deep-rooted racial bias in the city's mostly white police force had created a "toxic environment" in the predominantly-black community.

The protesters at the Ferguson rally had been demanding police reforms. Obama, the United States' first black president, said such protests were warranted in the light of events in the city, but said criminal acts could not be justified.

"What had been happening in Ferguson was oppressive and objectionable and was worthy of protest," he said during an appearance on the ABC program "Jimmy Kimmel Live".

"But there was no excuse for criminal acts, and whoever fired those shots shouldn't detract from the issue. They're criminals. They need to be arrested," Obama said.

The scene of the shooting has been the site of regular demonstrations since the fatal shooting in August of an unarmed black 18-year-old Michael Brown by a white policeman.

That killing triggered protests around the country and prompted the Justice Department investigation as well as a contentious national discussion over the use of deadly force by police officers.