Violence that erupted in Ferguson after a US grand jury’s decision not to indict a white police officer in the death of an unarmed black teenager was the “worst” since August, when the unrest first started, police said on Tuesday.

“What I’ve seen tonight is probably much worse than the worst night we ever had in August,” Police Chief Jon Belmar told reporters. “I didn’t foresee an evening like this, I will be honest with you.”

Hundreds of people had already gathered in Ferguson, Missouri before sunset, expecting to hear a grand jury decision on whether officer Darren Wilson, 28, would be tried for his actions in the death of Michael Brown, 18, in August.

Belmar said at least a dozen buildings were set on fire, two police cars vandalized, and 29 people were arrested during Monday night protests. He added that no officers fired their guns or sustained serious injuries during the protests.

The police chief said there were no deaths during the riots.

“I’m very uplifted by the fact that we don’t have any loss of life, because that’s the main goal here,” Belmar said.

The long-awaited decision by the grand jury of nine whites and three blacks – that there was not enough evidence to indict Wilson in Brown’s death – triggered violence by demonstrators gathered in the suburb of St Louis.

The shooting in August set off weeks of protests and looting in the town of 20,000 people and provoked a police response that was widely criticized as heavy-handed. Demonstrators demanded that Wilson be prosecuted for murder or manslaughter, while his supporters said he acted in self defence. SAPA