Police just shot smoke grenades moving people back, at corner where a lot of the action has occurred.

BALTIMORE (AP) — A line of police behind riot shields hurled smoke grenades and fired pepper balls at dozens of protesters Tuesday night to enforce a citywide curfew, imposed after the worst outbreak of rioting in Baltimore since 1968.

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 Rev. 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.

“This combined force will not tolerate violence or looting,” Gov. Larry Hogan warned.