North Korea and Iran resumed cooperation on the development of long-range missiles in 2020, according to a United Nations report that also confirmed Pyongyang continues to violate various nuclear resolutions.
The annual report, produced by an independent panel of UN experts, was submitted to the Security Council on Monday and seen by AFP.
It said Tehran denies any such missile cooperation with North Korea.
But according to an unnamed member state, North Korea and Iran "have resumed cooperation on long-range missile development projects," the report states.
"This resumed cooperation is said to have included the transfer of critical parts, with the most recent shipment associated with this relationship taking place in 2020."
In a December 21 reply, Iran stated the "preliminary review of the information provided to us by the [experts] indicates that false information and fabricated data may have been used in investigations and analyses."
In their assessment of North Korea, the experts said Pyongyang "maintained and developed its nuclear and ballistic missile programs, in violation of UN Security Council resolutions."
Pyongyang last year announced preparation for testing and production of new ballistic missile warheads and the development of tactical nuclear weapons.