Mayor Michael Bloomberg is underwriting a rally against gun violence and march across the Brooklyn Bridge to City Hall. View Full Caption DNAinfo/Colby Hamilton

MANHATTAN — Former Mayor Michael Bloomberg is underwriting a gun control demonstration at City Hall this weekend, DNAinfo New York has learned.

The rally is scheduled for Saturday morning at 10 a.m. with protesters gathering in Cadman Plaza in Downtown Brooklyn and then marching across the Brooklyn Bridge to City Hall.

Speakers and demonstrators will not be allowed inside City Hall grounds or onto the front steps of the building where Bloomberg worked for a dozen years, sources said.

Instead, the parade permit lets attendees congregate outside the gates and fences surrounding City Hall Park, where they will listen to speeches calling for tighter gun control and initiatives to reduce gun violence, sources said.

Bloomberg is not expected to attend, sources said, adding that organizers received the city's permission for "everything they requested."

The event is sponsored by several entities funded by the former billionaire mayor, including Moms Demand Action for Gun Sense in America, Everytown For Gun Safety and Bloomberg's Washington-based lobbying organization, Mayors Against Illegal Guns.

According to the insiders, Mayors Against Illegal Guns, which Bloomberg created in 2006, picked up the tab for the parade permits and for additional security to safeguard speakers and marchers.

"Mike Bloomberg is paying for the permits and just about everything else," one source said.

For its part, the NYPD is already preparing for thousands of demonstrators and has ordered dozens of officers to be posted on both sides of the Brooklyn Bridge and to escort marchers to and from City Hall.

Erika Soto Lamb, a spokeswoman for the event, said the rally is the second annual gathering by Moms Demand Action and Everytown, and they expect hundreds of mothers from across the country to attend.

Among those scheduled to speak are Shannon Watts, who founded Moms Demand Action following the Sandy Hook shooting on Dec. 14, 2012. She modeled the organization on Mothers Against Drunk Driving.

In addition, actress Amanda Peet will address the crowd along with Erica Lafferty, whose mother, Dawn Hochsprung, was the principal of Sandy Hook Elementary School and was killed. Local women affected by gun violence are also expected to speak.

On Thursday, the city's first lady, Chirlane McCray, sent out an email detailing her support for Gun Violence Awareness Month, and she has done numerous public service messages supporting the cause.

It was not clear whether she would attend the rally.

The demonstration comes in the aftermath of a string of deadly shootings in Las Vegas, Santa Barbara, Calif., and Portland, Ore., and it dovetails with a 10 percent spike in shootings in New York City since Bloomberg left office.

Bloomberg became an outspoken national leader calling for tougher restrictions on the sales of weapons during his administration.

He even began pumping millions of dollars from his own wealth into the campaigns of politicians who support reforming firearm regulations. It is a mission he has vowed to continue financing in the coming years.