Demonstrators threw bottles at police, and picked up the smoke grenades and hurled them back at officers.

No immediate arrests or serious injuries were reported. The clash came after a day of high tension but relative peace in Baltimore, as thousands of police officers and National Guardsmen poured into the city to prevent another round of rioting like the one that rocked the city on Monday.

It was the first time since the assassination of the Reverend Martin Luther King Jr. in 1968 that the National Guard was called out in Baltimore to prevent civil unrest.

Maryland's governor said 2,000 Guardsmen and 1,000 law officers would be in place overnight.

The racially charged violence on Monday by set off by the case of Freddie Gray, a 25-year-old black man who died of a spinal-cord injury under mysterious circumstances while in police custody.