Brian Snyder / Reuters
A worker installs a piece of security equipment on a lamp post on a bridge over the Charles River in Boston, Massachusetts July 2, 2013, in preparations for the city's Fourth of July celebrations. Security officials said they would deploy record numbers of police and install scores of new surveillance cameras and checkpoints around fireworks displays, concerts and other Fourth of July events in Boston, New York, Washington and Atlanta.
Cities across the country are ramping up security to unprecedented levels around Fourth of July celebrations this week, as law enforcement officials prepare for some of the largest public gatherings since the Boston Marathon bombings in April.
"The increase [in security] is, of course, related to the Marathon bombing and other global events," David Procopio, a spokesman for the Massachusetts State Police, told Reuters.
In Boston, security officials say state police will deploy additional uniformed and undercover troopers along the Charles River Esplanade, where thousands are expected to gather to watch the annual Boston Pops Fireworks Spectacular.
Backpacks, coolers with wheels, and pre-mixed beverages will be banned. Liquid containers cannot be more than two liters and must be clear plastic, law enforcement officials told NBC.
The secure perimeter around the festivities will be expanded and all people inside that area will have to pass through security screening gates. After 4 p.m., no items will be allowed to be carried in except chairs, tarps, and blankets.
Boston bombing suspect Dzhokhar Tsarnaev and his brother originally planned to carry out their attack on the Fourth of July, according to investigators, but after completing their pressure-cooker explosives earlier they carried out the plot in the spring.
Authorities say they have no intelligence of a specific threat of attack this week but major cities like New York, Washington, D.C., Philadelphia and Atlanta are not be taking any chances either.
In Washington, where hordes of tourists flock to the National Mall to see fireworks over the nation’s capital, perimeter chain link fencing will be extended from previous years to 18,000 linear feet, according to law enforcement officials. Bike racks will replace the wooden snow fences of previous years to help protect the perimeter.
As in past years, anyone trying to get to the National Mall will need to go through a checkpoint, NBCWashington.com reports.
New York City, which has deployed an increased police presence on the Fourth for years, will have even more manpower on the streets this Independence Day, authorities said.
Visitors to the Statue of Liberty, which reopens on July 4 for the first time since Hurricane Sandy hit last October, will be screened before boarding ferries.
And Philadelphia will increase security around the city’s most sensitive locations, like the Liberty Bell and Independence Hall, according to law enforcement officials.
Meanwhile, those celebrating in Atlanta are being asked by law enforcement not to bring any bags to public events. Extra security will be in place in the city’s Piedmont Park, where the annual Peachtree Road Race finishes.
"There should not be a single spot on the route that does not have camera coverage,'' Atlanta Police Chief George Turner told Reuters.
He added, "The specter of what happened in Boston with the marathon on April 15 weighs heavily on our hearts and minds."
The National Explosives Task Force (NETF) meanwhile said it has urged fireworks sellers in the U.S. to report buyers who raise suspicion. The Boston bombers used materials from fireworks to build their bombs, as had a man convicted of attempting to bomb New York's Times Square in 2010.
The NETF said in an industry advisory that fireworks sellers should look out for people with "injuries consistent with experimentation with explosives such as missing hand/fingers'' or who are "making suspicious comments regarding radical theology, anti-U.S. sentiment."
Reuters contributed to this report.