A Chinese man living in the U.S. illegally was arrested Tuesday and accused of exporting guns and ammunition to North Korea and of planning to send other technology to the nuclear-armed pariah state.

Shenghua Wen, 41, was living in Ontario, in Southern California east of Los Angeles, on an expired visa when he conducted the illicit trade, officials said.

At least two shipments of firearms and ammunition were sent, hidden in shipping containers, from the port in Long Beach and on to Hong Kong and then North Korea, according to court documents.

“The significance of this arrest and discovery of this scheme cannot be overstated,” Akil Davis, assistant director in charge of the FBI’s Los Angeles field office, said in a statement.

Law enforcement seized some material in the U.S. before it could be shipped, officials said.

In September, authorities searched Wen’s home and found around 50,000 rounds of 9 mm ammunition and a receiver that detects eavesdropping devices, the U.S. attorney’s office in Los Angeles said.

Wen came to the U.S. on a student visa in 2012 but stayed after it expired, according to an affidavit filed as part of the criminal complaint.

Wen told U.S. investigators that before he came to the U.S. he had met with North Korean officials at consulates in China and that they instructed him to send goods to North Korea, which is under severe sanctions restricting trade, according to the affidavit.

Wen said that in 2022, he was contacted by two North Korean officials in China who wanted him to send guns and ammunition to North Korea, the affidavit alleges.

Wen bought the guns through straw buyers, mostly in Texas, and drove them to California, according to prosecutors. He “stated that it was a simple process for him to purchase firearms,” the affidavit alleges.

He is accused of working with other, unnamed co-conspirators. The author of the affidavits is redacted, and some other information in the document is redacted, as well.

The North Korean officials had more than guns and ammunition on their minds, according to the affidavit.

Wen told investigators that the officials he was in contact with wanted him to send civilian aircraft engines to help the North Korean military's drone program, the affidavit author wrote.

Wen's phone showed messages about a part and controller of the Star Safire system, a military video and infrared system for use on aircraft, the affidavit says.

The North Korean officials also asked for military uniforms, which Wen said he believed would be used to help launch a surprise attack against South Korea, the document says.

Online court records did not appear to show Wen's case in publicly available documents, and it was not clear whether he had an attorney who could speak on his behalf Tuesday afternoon.

Wen is charged with conspiracy to violate the International Emergency Economic Powers Act. If he is convicted, that charge carries up to 20 years in prison, the prosecutor's office said.