Newark, N.J., Mayor Cory Booker (D) formally announced his candidacy for the U.S. Senate on Saturday.

"I'm here today to officially announce my candidacy to be New Jersey's next United States senator," Booker, speaking at the headquarters of, a company that moved Newark in 2007, said.

Booker was introduced by former Sen. Bill Bradley (D-N.J.), who Booker praised as a "giant" in the Senate.

Booker specifically mentioned gun violence and job creation in his speech.

"We have challenges, even with the progress we've made I see here in Newark and across the state too few jobs, too much gun violence, too many students coming up short," Booker said. "But despite the challenges there is something that we know in our gut: that we as a people are so much bigger than any of our challenges."

The Newark mayor also referred to immigration reform, a primary topic of debate on Capitol Hill.

"It is not anymore of 'can we?' It is a question of 'do we have the collective will?' " Booker said.

"Think about it, we have a shortage of good paying jobs and yet we refuse to invest in the infrastructure that will put construction workers back to work and strengthen American competitiveness. Think about it: we have millions of people willing to help our country by working hard and paying taxes, many of them are here at our finest New Jersey universities, they are trained and ready to contribute and yet the path to comprehensive immigration reform still remains uncertain, denying our state the economic growth many residents of our state could bring."

Booker said his record as mayor of Newark showed that he has been successful at bringing people together. He touted that in the past few years Newark has attracted a number of new companies to the city like Manischewitz and Panasonic.

"The truth is, ultimately, with the United States Senate in Washington, D.C., that it'll be hard for any single United States senator to make the kind of difference we need," Booker added. "But New Jersey is used to doing what is hard, doing it not alone with an individual but by doing it together."

Booker's announcement comes less than a week after Sen. Frank Lautenberg (D-N.J.) died. New Jersey Gov. Chris Christie (R) announced a special election for Oct. 18. and selected New Jersey Attorney General Jeff Chisea (R-N.J.) as interim senator until the election.