NEWARK, N.J. (AP) — The mayor of Newark imposed a curfew early Sunday around an immigration detention center in New Jersey after a series of intense clashes between protestors and police.

The curfew around Delaney Hall will be in place between 9 p.m. and 6 a.m. until further notice, Mayor Ras Baraka said in a statement.

The move came after another night of standoffs between law enforcement and demonstrators at the facility, as protestors could be seen in photographs and videos fighting over barricades as police used riot shields to push them back. A video posted on social media showed police on horseback marching into crowds attempting to break up groups of protestors.

The demonstrations at Delaney Hall began earlier this month after advocates said detainees inside launched a hunger strike over poor living conditions at the 1,000-bed facility, the latest hotbed of opposition over the federal government’s immigration crackdown.

New Jersey state police on Friday relieved federal immigration enforcement agents who had been facing off against protestors at the facility for days.

In a statement Sunday morning, New Jersey Gov. Mikie Sherrill said masked individuals attacked a barrier in a designated protest area set up by state police and were “throwing projectiles, utilizing the barriers as weapons, and lighting tires on fire in the street.”

“These actions put both peaceful protestors and law enforcement in danger,” Sherrill said, urging calm to focus on advocating for “better conditions for the detainees, for their families, and ultimately, for the closure of Delaney Hall.”