Washington: The Federal Bureau of Investigation (FBI) of the United States has reportedly tracked around 100 incidents where Chinese nationals, sometimes posing as tourists, have accessed military bases and sensitive sites in America, the Wall Street Journal reported.

The US officials have described the incidents as potential espionage threats.

The Defense Department, FBI and other agencies held a review last year to try to limit these incidents, which involved “gate-crashers” because of their attempts to get into US military bases without proper authorization, the WSJ report said.

Those responsible range from Chinese nationals detected crossing into a US missile range in New Mexico, to scuba divers caught swimming in murky waters near a government rocket launch site in Florida, several officials recently told The Wall Street Journal.

Some of the authorities believed that the Chinese government in some cases are compelling its citizens to test out the service and report back regarding the security practices at the installations.

In response to the report, an FBI spokesperson stated, "The greatest long-term counterintelligence threat to our nation’s information and intellectual property is from China."

"The Chinese government is engaged in a broad, diverse campaign of theft and malign influence without regard to laws or international norms that the FBI will not tolerate," an FBI spokesperson told Fox News Digital.

"In coordination with our defence and intelligence community partners, along with state and local law enforcement, the FBI is committed to protecting our national security and defence information from the Chinese government's actions and ultimately, their efforts to undermine our democracy and those who defend it," the spokesperson added.

According to Fox News citing the Wall Street Journal, recently a group of Chinese nationals arriving at Fort Wainwright, Alaska, claimed that they had reservations at a commercial hotel on the base and tried to make their way past guards.

Notably, Fort Wainwright is home to the US Army’s 11th Airborne Division focused on Arctic warfare.

"The security of our installations remains a top priority for the Department. Physical security standards for our bases take into consideration a wide variety of potential threats, including attempted spying by our adversaries," a Defence Department spokesperson also told Fox News Digital, reacting to the report.

"We work with local, State, and Federal law enforcement officials, the intelligence community, and our foreign partners to protect our military bases against these threats at home and abroad," the spokesperson added.

The Department of Defence (DoD) "has conducted several base security reviews since 2018, some of which included support by interagency partners," the spokesperson continued. "A recent review focused on the physical security condition of our gates, among other aspects of base security. The results of the reviews have and will continue to inform changes to the protective posture of our bases."

"Every day DoD conducts more than 10,000 ‘controlled turnarounds’ of individuals who arrive at one of our 1400 gates. These individuals are not authorized to access and depart the installations without having gained unauthorized access," the Defence spokesperson said.

Officials told the Wall Street Journal the incidents have occurred in rural areas where tourism is less common and far from a commercial airport. They said the Chinese nationals often use what officials described as scripted language, claiming when stopped that they are tourists who have lost their way.

This type of low-level Chinese intelligence collection is more of a numbers game, a former Senate Intelligence Committee official told the Journal, explaining how the Chinese government is willing to throw numerous people at collection, knowing that if a few get caught it will be difficult for the US government to prove anything nefarious beyond trespassing.

The WSJ reported that repeat incidents have occurred at an intelligence centre based in Key West, Florida, dating back to a few years ago involving Chinese nationals found swimming in nearby waters and taking pictures.