Chinese nationals, who sometimes posed as tourists, accessed U.S. military bases and other sensitive sites around 100 times in recent years, according to an exclusive report by The Wall Street Journal.

The newspaper cited U.S. officials, who described the incidents as potential forms of espionage.

Last year, the U.S. Department of Defense, FBI, and other agencies held a review to try to curb the frequency of these breaches, which involved unauthorized entries into US military bases and other federal sites, the newspaper reported.

Most of the incidents took place in rural areas, away from tourist hotspots and commercial airports, according to the Journal.

In one such incident, Chinese nationals were found scuba diving off Cape Canaveral, home to the Kennedy Space Center, per the Journal.

At another site in Florida — an intelligence center in Key West — there have been repeated incidents of Chinese nationals posing as tourists swimming near the facility and taking pictures, officials said, according to the Journal.

In at least one instance, an incursion there has led to arrests, with three Chinese citizens receiving prison sentences in 2020 after pleading guilty to illegally entering a naval air station in Key West and taking photos, the newspaper said.

Other instances highlighted by the Journal include a group of Chinese nationals claiming to be tourists who tried to push past guards at Fort Wainright, Alaska, saying they had a reservation at a hotel on the base. The base is home to an army division focused on Arctic warfare, the newspaper said.

However, other examples of gate-crashing appear relatively innocuous, said people familiar with the review. These involved Chinese nationals who claimed their Google Maps had directed them to the nearest fast-food restaurant, which happened to be near military bases, per the Journal.

But officials noted to the Journal that many individuals who have been confronted by security officials have responded with language that appears scripted, saying they are merely lost tourists.

This Sept. 11, more than 60 Veterans Affairs cemeteries will hold volunteer events as part of the National Day of Service, welcoming VA employees, veterans, family members and the public to take part in beautification efforts on their grounds.

The events are meant to honor the service members, veterans, law enforcement officers, firefighters and other first responders who served on that day, as well as post-9/11 veterans who gave their lives for their country in the past 22 years, according to the VA.

"On 9/11, we encourage all Americans to join us at one of our national cemeteries to volunteer and pay tribute to our nation's heroes," Under Secretary for Memorial Affairs Matt Quinn said in a release Thursday. "By volunteering on this day of service, by cleaning a headstone and saying their names, we tell these heroes our nation has not forgotten all they sacrificed for us."

Volunteers largely will clean headstones at 66 participating national cemeteries, but they may be asked to plant flags or participate in other projects at the sites.

Two years ago, VA Secretary Denis McDonough and wife Kari volunteered at Quantico National Cemetery in Virginia, scrubbing grave markers and placing American flags at gravesites.

"We wanted to demonstrate that this is an ongoing commitment, especially, to our 9/11 vets," McDonough said in an interview Thursday. "The idea is to get out, particularly on that day, to demonstrate again that we do not forget and we will not forget."

Volunteers have dedicated Sept. 11 as a day to engage in charitable service since the first anniversary of the 2001 terrorist attacks. But Congress established Sept. 11 as a National Day of Service and Remembrance in 2009. That same year, President Barack Obama amended President George W. Bush's proclamation designating Sept. 11 as Patriot Day also as a day of service and remembrance.