WASHINGTON -

U.S. Sen. Frank Lautenberg, D-N.J., has announced he will not seek re-election.

The 89-year-old lawmaker is the last remaining veteran of World War II in the Senate and has been elected easily five times but was facing a likely challenge from charismatic Newark Mayor Cory Booker.

Lautenberg is a staunch advocate of gun control and public infrastructure and is a champion of the Amtrak railroad.

Lautenberg first won election to the Senate in 1982.