WASHINGTON — Republican White House hopeful Mitt Romney will head out on a bus tour across battleground states in mid-August in the run up to the party convention in Tampa, Florida, his campaign said Tuesday.

Details were still being worked out, but an official in the campaign told AFP that the bus tour -- Romney's second since clinching his party's nomination in April -- will carry him through swing states widely seen as crucial to the outcome of the November election.

The roll out is expected on or shortly after August 10, some two and a half weeks before the Republican convention, when Romney is expected to be officially crowned the nominee.

The timing is leading to speculation that Romney, fresh off a heavily criticized trip to Britain, Israel and Poland that concluded Tuesday, may announce his running mate at that time and then head out on the road with him -- or her.

Sources familiar with the plans described to CNN a four-day bus tour through Virginia, North Carolina and Florida, and said prominent Republicans and campaign surrogates would join Romney at each of the stops.

"Sounds like VP week," CNN quoted a Republican familiar with the schedule but who did not want to be identified discussing campaign plans.

"Hitting the big markets in the big states. It just makes sense."

Romney is locked in a neck-and-neck race for the White House against President Barack Obama. Both campaigns have acknowledged the importance of about 10 swing states where the outcomes will likely decide the election.