Fourth of July celebrations started in Washington, D.C., with a parade along Constitution Avenue and were to end with fireworks over the Washington Monument.

President Barack Obama and first lady Michelle Obama invited about 1,200 military families for festivities Saturday night. Vice President Joe Biden spent the Fourth of July in Iraq, presiding over a naturalization ceremony for 237 U.S. troops from 59 countries. He had lunch with the 261st Theater Tactical Signal Brigade from Delaware, to which his son, Beau, belongs.

In rural Oklahoma, former President George W. Bush spoke amid thunderous applause, calling the U.S. the "greatest nation on the face of the Earth."

Bush was given six standing ovations as he spoke Saturday inside a remodeled rodeo arena in Woodward, a town of about 12,000 residents in northwest Oklahoma. About 9,200 tickets were sold for the event, which would be the biggest crowd for Bush since he left office in January.