Top Republicans close to Mitt Romney's campaign has told the Associate Press that the U.S. presidential candidate has chosen Paul Ryan to be his running mate.

Romney was expected to introduce Ryan the Congressman of Wisconsin during a rally today in Norfolk, Virginia at the start of a bus tour on through four battleground states he needs to win in November Virginia, North Carolina, Florida and Ohio.

Conservatives have been urging Romney to pass over tried and true Republicans like Ohio Senator Rob Portman and former Minnesota Governor Tim Pawlenty and go big with 42-year-old Ryan.

For Romney, an outsider to Washington, Ryan would provide some expertise in dealing with Congress.

But as a long-time member of the House, he lacks executive experience.