GLEN, NH/new york - US Democratic presidential candidate Hillary Clinton has accused China of stealing commercial secrets and “huge amounts of government information,” and of trying to “hack into everything that doesn’t move in America.”

Clinton’s language on China appeared to be far stronger than that usually used by President Barack Obama’s Democratic administration. Speaking at a campaign event in New Hampshire, Clinton said she wanted to see China’s peaceful rise.

“But we also have to be fully vigilant, China’s military is growing very quickly, they’re establishing military installations that again threaten countries we have treaties with, like the Philippines because they are building on contested property,” said Clinton, who was secretary of state from 2009 to 2013. “They’re also trying to hack into everything that doesn’t move in America. Stealing commercial secrets ... from defense contractors, stealing huge amounts of government information, all looking for an advantage,” she said.

Clinton is the front-runner to win the Democratic nomination for the November 2016 presidential election.

Asked about the remarks, a White House official declined to comment.

Meanwhile, despite threats of terrorist attacks, Americans celebrated 239 years as an independent nation on Saturday with spectacular fireworks displays, rock and classical concerts and parades both big and small.

With presidential election due next year, candidates for the nation's top post from both parties - Republicans and Democrats, joined the colourful parades that took places in various cities across the United States. Hundreds of thousands of people braved tight security along New York City's East River to watch the annual the Fourth of July fireworks display, which was sponsored by Macy's, a departmental store.

Macy's said the 25-minute show featured more than 50,000 shells set off from five barges on the river. The fireworks show was broadcast live on NBC, an American television network. The tight security included police officers searching backpacks and purses. Other officers used hand-held radiation detectors to scan baby carriages and large suitcases.

Security officials said that celebrations this year faced what some call the most serious threats since 2001.

"The threat stream is very high," Los Angeles Deputy Police Chief Michael Downing said. "In fact, we don't think it's been this high since 9/11." People attending the fireworks on the National Mall had to pass through one of 11 checkpoints set up to keep visitors safe, and in New York City 7,000 extra officers were deployed for the fireworks. In Chicago, police were put on 12-hour shifts for the holiday.

Alongside the patriotic music and waving flags in parades across Iowa and New Hampshire were clear reminders of a upcoming presidential race. Red balloons promoting "Jeb! 2016," - Jeb Bush - a tractor draped in a Rick Perry, another Republican banner and dutiful volunteers holding signs and chanting for their chosen candidates.

Marching in Fourth of July parades in these early voting states has become a tradition for politicians seeking the White House, giving them a chance to boost their name recognition and glad-hand with voters. Former Governors Jeb Bush of Florida, Rick Perry of Texas and Lincoln Chafee of Rhode Island as well as South Carolina Senator Lindsey Graham worked the crowd in Amherst, Mass, while Hillary Rodham Clinton marched in a parade in New Hampshire's North Country. New Jersey Governor Chris Christie and Florida Senator Marco Rubio spent the holiday in New Hampshire's Lakes Region, as Louisiana Governor Bobby Jindal, Vermont Senator Bernie Sanders and former Maryland Governor Martin O'Malley met voters in Iowa.

Clinton marched in a Fourth of July parade in Gorham, New Hampshire, trailed by a band of supporters waving signs and separated by a long rope from the pack of journalists that followed.

"I'll tell you what - we need to get a Democratic president," Clinton told one woman along the parade route, who asked about the health care overhaul. "I'm going to not only defend it, I'm going to make it even better."

One man who carried a sign that read, "Benghazi" also followed the candidate. Alluding to her time representing New York in the Senate, he screamed repeatedly, "Carpetbagger!" Another man on the route yelled, "What about Benghazi? What about the emails?" Clinton smiled broadly, shaking hands and stopping for quick photos. At one point, she posed for a photo with two New Hampshire beauty pageant contestants, who playfully flexed their biceps.