NEW YORK (CBSNewYork) — NYPD officers in riot gear cleared Occupy City Hall protesters from their encampment before dawn Wednesday.

Several hundred officers moved in around 3:40 a.m., making seven arrests.

Chief Raymond Spinella said one officer had a brick thrown at him, but was not hurt. Otherwise, he said, the operation “went smoothly.”

“The police department has closely monitored the situation at the park since its inception,” he said. “We felt the time had come to end the occupation and allow cleanup crews to begin the process of removing the graffiti.”

Earlier this week, Mayor Bill de Blasio said the NYPD would decide when to clear the park.

CBS2’s political reporter Marcia Kramer asked the mayor what changed Wednesday.

“The gathering there got smaller and smaller, was less and less about protest, and more and more it became an area where homeless folks were gathering,” de Blasio replied. “I said repeatedly, we do always respect the right to protest, but we do have to think about health and safety first – and the health and safety issues were growing.”

WATCH: NYPD Officials Address Reporters After Clearing Occupy City Hall 

He said the Department of Homeless Service was also on scene to help connect people with services.

“There’s been regular efforts by Homeless Services to engage folks who are there. They’ve been out there again today,” he said. We want to make sure that as many people as possible will accept the shelter we have for them, hopefully turn their life around and not go back to the streets.”

Protesters spent the past month occupying City Hall Plaza, calling to defund the NYPD, help the formerly incarcerated and provide affordable housing.

Spinella said the area will be closed for weeks as crews begin the cleanup process.

PROTESTS AND POLICE REFORMS

Check back with CBSNewYork.com for more on this developing story.