Updated

The U.S. Department of Justice arrested two U.S. Navy sailors on national security charges relating to China on Thursday.

It is unclear whether the two cases are connected in any way. Jinchao Wei, aka Patrick Wei, a 22-year-old assigned to a vessel in San Diego, was arrested on an espionage charge relating to a conspiracy to share intelligence with a Chinese official.

Wei was an active-duty sailor on the U.S.S. Essex, an amphibious assault ship stationed at Naval Base San Diego. He is accused of sharing photos and videos of the Essex, disclosing the location of Navy ships and describing the Essex's defensive weapons to a Chinese intelligence officer in exchange for thousands of dollars.

The second sailor, Petty Officer Wenheng Zhao, aka Thomas Zhao, 26, of Monterey Park, California, is charged with conspiracy and receipt of a bribe from a Chinese official. Zhao worked at Naval Base Ventura County in Port Hueneme and held a U.S. security clearance.

Zhao is accused of secretly recording U.S. military information, photographs and videos and then transmitting to a Chinese intelligence officer posing as a maritime economic researcher in exchange for bribes. Electrical diagrams and blueprints for a radar system stationed on a U.S. military base in Okinawa, Japan were some of the materials shared with the Chinese intel officer.

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An Arleigh Burke-class destroyer

The U.S. Department of Justice arrested two U.S. Navy sailors on national security charges relating to China on Thursday. (James D. Morgan/Getty Images)

"In the first case out of the central district, the defendant, a petty officer who served as a construction engineer, is charged with conspiring with a PRC intelligence officer to collect and transmit sensitive military information about naval operations," Assistant Attorney General Matthew Olsen said during a Thursday press briefing. 

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"The defendant allegedly accepted bribes and gave the PRC intelligence officer photographs and videos of military exercise plans, operational orders and electrical systems," he added.

Justice Department

The DOJ charged two U.S. Navy sailors with espionage-related crimes in California. (Kevin Dietsch/Getty Images)

The bribes paid to Zhao totaled $14,866, according to an indictment. The petty officer faces up to 20 years in prison if convicted.

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"As tasked by the intelligence officer, the defendant allegedly transmitted or attempted to transmit more than 50 manuals and other documents containing technical and mechanical data about naval amphibious assault ships," Olsen said. "Several of these materials were allegedly marked with export control warnings and contained details about the power structure, weapons systems and damage control aboard those ships."

Chinese President Xi Jinping in blue suit and blue tie speaking at 100th anniversary of CCP event

China conducts extensive operations to steal information from the U.S. military and private U.S. businesses. (Xinhua/Shen Hong via Getty Images)

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Olsen said China "stands apart" from all other adversarial nations in the threat it poses to the national security of the U.S. 

"China is unrivaled in the audacity and the range of its malign efforts to subvert our laws," Olsen said Thursday.

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A Pentagon spokesman was asked about the cases Thursday.

"Without getting into specific cases, as we've talked about before, I think we have clear policies and procedures in place when it comes to safeguarding and protecting sensitive information," Brig. Gen. Patrick Ryder said. "And so if those rules are violated, the appropriate action will be taken as it has in the cases that were highlighted."