FIRST ON FOX: Top House Republicans are demanding Homeland Security Secretary Alejandro Mayorkas brief lawmakers on the actions agency officials have taken to address potential security vulnerabilities at U.S. ports related to the use of Chinese-manufactured cranes.

The lawmakers first wrote to Mayorkas demanding the information and a briefing on April 3, and told Fox News Digital that DHS has not yet complied. 

House China Select Committee Chairman Mike Gallagher, R-Wis., and House Homeland Security Committee Chairman Mark Green, R-Tenn., sent another letter to Mayorkas Friday, sounding the alarm on the use of China-made cranes at U.S. ports, warning of "cyberattacks, espionage, and supply chain vulnerabilities."

"We remain concerned about the security risks associated with the widespread use of Chinese-manufactured cranes that threaten to undermine our national security, particularly those made by Shanghai Zhenhua Heavy Industries (ZPMC), a Chinese state-owned business whose governing shareholder is China Communications Construction Company," they wrote, demanding information "on the prevalence of such equipment and technology at U.S. ports and DHS actions to address the potential national security threats posed by the Chinese Communist Party’s use of this technology in U.S. port infrastructure."

GIMENEZ, GARAMENDI TO ROLL OUT BIPARTISAN BILL TO COMBAT CCP 'UNDUE INFLUENCE' AT US PORTS

Mike Gallagher at House Select China Committee

Chairman Rep. Mike Gallagher, R-Wis., listens during a hearing of a special House committee dedicated to countering China, on Capitol Hill, Tuesday, Feb. 28, 2023, in Washington. (AP Photo/Alex Brandon)

The lawmakers said ZPMC has operated "under the umbrella of the Chinese state since its conception and has rapidly grown to be the dominant global manufacturer of ship-to-shore cranes." 

They warned that ZPMC "controls around 70 percent of the global market share for cranes and accounts for nearly 80 percent of the ship-to-shore cranes in use at U.S. ports, posing significant risk to U.S. homeland security."

ARE CHINESE CRANES BEING USED FOR SURVEILLANCE AT US PORTS? HOUSE GOP VISITS PORT OF MIAMI TO FIND OUT

"These security risks include cyberattacks, espionage, and supply chain vulnerabilities due to the shared software and interconnectivity among ZPMC cranes operating at our nation’s ports," they wrote.

Rep. Mark Green speaking at an event

Rep. Mark Green, R-Tenn.

They added, "ZPMC cranes pose a potential risk for intelligence gathering purposes and we find it disconcerting that CCP-backed entities may use their access to ZPMC cranes to target and disrupt our nation’s ports in the event of a Chinese invasion of Taiwan."

Gallagher and Green are demanding all records related to ZPMC and any other Chinese-based manufacturer from 2000 to present; all records to describe how DHS has assessed and mitigated the risks associated with the Chinese software and operational technology at U.S. ports; and any records related to outreach efforts made to foreign allies and partners to "raise awareness about the risks of Chinese software and operational technology in their ports."

Gallagher and Green are also demanding information on "all known or suspected incidents of cyber-attacks or espionage linked to Chinese software and operational technology in U.S. ports from January 1, 2000, to the present," as well as any efforts the Biden administration is taking to create or secure "alternatives" to Chinese software and operational technology in U.S. ports.

Mayorkas testifying senate

Secretary of Homeland Security Alejandro Mayorkas speaks during a hearing with the Senate Homeland Security Committee in the Dirksen Senate Office Building on April 18, 2023 in Washington, D.C. (Anna Moneymaker/Getty Images)

CHINA ON ‘DISTURBING’ PATH TO ECLIPSE US MILITARY BY MID-CENTURY, MILLEY WARNS

House Subcommittee on Transportation and Maritime Security Chairman Carlos Gimenez, Subcommittee on Cybersecurity and Infrastructure protection Chairman Drew Garbarino; Subcommittee on Oversight, Investigations and Accountability Chairman Dan Bishop; and Subcommittee on Counterterrorism, Law Enforcement and Intelligence Chairman August Pfluger also signed onto the letter.

The lawmakers demanded the Department of Homeland Security provide the records by May 24, and set up a staff-level briefing by May 31.

"DHS responds to Congressional correspondence directly via official channels, and the Department will continue to respond appropriately to Congressional oversight," a DHS spokesperson told Fox News Digital when asked to comment on the letter.

Carlos Gimenez and Mike Gallagher standing next to each other

Rep. Carlos Gimenez, left, speaks at a podium at the Port of Miami, with Rep. Mike Gallagher, right. (Gimenez)

The letter comes after a congressional delegation from the House China Select Committee visited the Port of Miami to inspect Chinese-made cranes, amid fears that Beijing-made infrastructure could be conducting surveillance on U.S. ports and pose a risk to national security. 

The visit came amid reports that suggested that the Pentagon is now viewing giant cargo cranes as possible Chinese spying tools. The reports suggested Chinese equipment at ports could be used for surveillance.

US INTEL COMMUNITY WARNS OF 'COMPLEX' THREATS FROM CHINA, RUSSIA, NORTH KOREA

"There is zero evidence to support sensationalized claims that our equipment isn’t secure," stated Chris Connor, president and CEO of the American Association of Port Authorities. "As we have already stressed, the cranes our ports procure, based on cost, use separate software purchased from allied countries like Japan and Sweden, and they undergo rigorous security inspections with federal government partners to safeguard against cyber threats."

Lawmakers at a port in Miami

Rep. Gimenez, left, and Rep. Mike Gallagher, right, visit the Port of Miami. (Gimenez)

In its annual threat assessment last month, the U.S. intelligence community warned that China represents the "broadest, most active, and persistent cyber espionage threat to U.S. Government and private-sector networks."

CLICK HERE TO GET THE FOX NEWS APP

"China’s cyber pursuits and its industry’s export of related technologies increase the threats of aggressive cyber operations against the U.S. homeland," officials warned, adding that China is "capable of launching cyberattacks that could disrupt critical infrastructure services within the United States, including against oil and gas pipelines, and rail systems."

Officials also warned that China is rapidly expanding and improving its surveillance, its artificial intelligence and big data analytics capabilities.