Frank Lautenberg, pictured here in 2006, will not run for another term. (AP Photo/Charles Dharapak)

Sen. Frank Lautenberg (D-N.J.) will not run for reelection, he announced Thursday, ending five terms in the Senate.

“I am not announcing the end of anything. I am announcing the beginning of a two-year mission to pass new gun safety laws, protect children from toxic chemicals and create more opportunities for working families in New Jersey,” the 89-year-old senator said in a statement. “While I may not be seeking re-election, there is plenty of work to do before the end of this term and I'm going to keep fighting as hard as ever for the people of New Jersey in the U.S. Senate.”

Lautenberg quipped to reporters Thursday that he had decided to announce his retirement because, “I looked out, and it’s time for me to be mature."