Republican U.S. Rep. Ryan says he's not running for president in 2016

WASHINGTON (Reuters) - Republican U.S. Representative Paul Ryan, the party's vice presidential nominee in 2012, said on Monday he will not run for president in 2016 in order to focus on his new role in Congress as chairman of the influential House Ways and Means Committee.

"After giving it a lot of thought, I've decided not to run for president," Ryan said in a statement provided by an aide.

The Wisconsin native, a stalwart budget conservative, had been considered a potential White House candidate since serving as Mitt Romney's vice presidential running mate in 2012.

His decision could have a ripple effect on what is expected to be a crowded Republican field for the 2016 race. It could benefit Wisconsin's Republican governor, Scott Walker, who is considering a run.

Ryan is chairman of the tax-writing House Ways and Means Committee. He said the committee's work over the next few years will be crucial "and my job as chairman deserves undivided attention.

"It's clear our country needs a change in direction. And our party has a responsibility to offer a real alternative. So I'm going to do what I can to lay out conservative solutions and to help our nominee lead us to victory," he said.

Ryan would have been a prominent contender in a highly competitive 2016 Republican field. Former Florida Governor Jeb Bush has said he is exploring a run, and Romney told donors on Friday he was still eyeing another bid.

Other potential contenders include Governors Rick Perry of Texas, John Kasich of Ohio and Chris Christie of New Jersey, along with Senators Ted Cruz of Texas, Rand Paul of Kentucky and Marco Rubio of Florida.

Ryan told NBC News he made the decision to pass up a White House bid "weeks ago," well before Romney's possible intentions became known.

Ryan, 44, would not rule out a run for higher office in the future, saying he plans to "keep my options open."

(Reporting by Eric Beech; Writing by John Whitesides; Editing by Peter Cooney and Dan Grebler)