The annual Independence Day celebration across the United States was capped off Wednesday with the traditional nighttime fireworks displays in many cities.

In Washington, D.C., a large crowd gathered at the U.S. Capitol for a patriotic concert watched as fireworks lit up the sky behind the Washington Monument, while New Yorkers were treated to a spectacular fireworks show above the famed New York Harbor, home of the Statue of Liberty.

Earlier Wednesday, U.S. President Barack Obama welcomed 25 active-duty U.S. service members as new American citizens sworn in at the White House. The president later paid tribute to the military families and invited them to join him for a barbecue and a performance by the U.S. Marine Corps Band.

“All of you represent what's best in America. You serve under our proud flag. You and your families sacrifice more than most of us can ever know, all in defense of those God-given rights that were first put to paper 236 years ago: life, liberty, and the pursuit of happiness.”

Mr. Obama's likely Republican opponent in the November general election, Mitt Romney, spent the holiday marching in a parade in New Hampshire, where he and his family are on vacation from the campaign trail.

This year's 4th of July holiday was a disappointing one for many Americans. More than one million people in the East are still without power after last Friday's vicious wind and rain storm. Millions are also sweltering through a brutal heat wave that has sent temperatures above 38 degrees Celsius in some places.

The heat, drought and wildfires still burning in the West forced authorities to cancel fireworks shows in cities and towns in 20 states.

This year's celebration marked the 236th anniversary of the country's declaration of independence from Britain, making it the United States' most cherished symbol of freedom. Drafted by Thomas Jefferson in June 1776, the Continental Congress formally approved the document weeks later, on July 4.