FERGUSON, Missouri: US police said early on Tuesday they came under heavy gunfire and arrested 31 people during another night of racially charged protests in Ferguson, Missouri, sparked by the fatal shooting of an unarmed black teenager by a white policeman 10 days ago.

Demonstrations, mostly peaceful but with spasms of violence by smaller groups, have flared since Michael Brown, 18, was shot dead while walking down a residential street on Aug. 9.

State Highway Patrol Captain Ron Johnson, briefing reporters on Monday’s night’s violence, said “our officers came under heavy gunfire” in one area.

“Not a single bullet was fired by officers despite coming under heavy attack,” he told a news conference. Riot police had confiscated two guns from protesters and what looked like a petrol bomb. Four officers had been injured.

Johnson separately told CNN that two people were shot within the crowd, but not by police, and were taken to hospital. There was no immediate word on their condition.

The violence has captured headlines around the world, raising questions about the state of US race relations nearly six years after Americans elected their first black president.