North Korea claimed Sunday that U.S. officials forcibly seized a diplomatic package from one of their delegations at John F. Kennedy Airport, calling it an “illegal and heinous act of provocation.”

The official Korean Central News Agency said officials were returning from a UN conference on rights of persons with disabilities Friday when they were “literally mugged.”

“At the airport, a group of more than 20 including those who claimed to be from the U.S. Department of Homeland Security and the police officers made a violent assault like gangsters to take away the diplomatic package from the DPRK (Democratic People’s Republic of Korea) diplomats who were in possession of a valid diplomatic courier certificate,” a spokesman for North Korea’s foreign ministry told the news agency.

“As the diplomats vigorously resisted, they grabbed the diplomatic package using physical violence and made off,” the North Korean spokesman said.

U.S. Department of Homeland Security spokesman David Lapan said Sunday its officers did seize multiple media items and packages from three North Koreans who, according to the U.S. State Department, were not accredited members of North Korea’s Mission to the U.N. and had no diplomatic immunity.

“The package in question had no diplomatic protection from inspection,” said Lapan, adding that North Koreans attempted to physically retrieve the items but were prevented from doing so by DHS officers.

“The reported aggression was initiated by the North Koreans,” Lapan said. “The individuals were released without further incident but subsequently refused to board their departing flight without the items that had been seized.”

It wasn’t immediately clear why the items were taken. The State Department in a statement confirmed the assertions by DHS that the package had no diplomatic protection and that the travelers weren’t accredited North Korean diplomats at the U.N., but offered no other details.

The incident comes days after 22-year-old American college student Otto Warmbier was returned to his home state of Ohio in a coma with severe brain damage after being imprisoned in North Korea for 17 months.

North Korea claims the coma resulted from botulism and a sleeping pill, but U.S. doctors said they found no evidence of active botulism, a rare, serious illness caused by contaminated food or a dirty wound.

(AP)