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."

"As the diplomats vigorously resisted, they grabbed the diplomatic package using physical violence and made off," the ministry insisted, according to Pyongyang's official KCNA news agency.

"If the U.S. fails to give its due response to our demand which is all too reasonable and fair enough, it will be totally responsible for all the consequences to be entailed," the statement added.

While it remains unclear exactly what was in the package or if the delegation had diplomatic immunity, there has been growing wariness around North Korean baggage and shipments since the poisoning of leader Kim Jong-un's half-brother at a Malaysian airport in February.

Ties between Pyongyang and Washington are also particularly frayed after an American college student imprisoned in the North for 17 months was recently returned to the U.S. in an unresponsive state.