North Korea has been working to protect its nuclear and ballistic missile capabilities from military strikes, according to UN monitors.

Citing a confidential report drafted by UN sanction monitors, Reuters on Monday said the group “found evidence of a consistent trend on the part of North Korea to disperse its assembly, storage and testing locations.”

The North Korean mission to the United Nations did not immediately respond to a request for comment on the 300-page report, which was submitted to a 15-member UN Security Council sanctions committee on Friday. 

The report argues that sanctions are proving ineffective. 

Reuters noted that this comes ahead of a meeting between U.S. and North Korean officials to prepare a second summit between President Donald Trump and the North's leader Kim Jong-un.