North Korea made preparations for a nuclear test during the first six months of this year, according to an excerpt of a confidential United Nations report seen by Reuters news agency.
"Work at the Punggye-ri nuclear test site paves the way for additional nuclear tests for the development of nuclear weapons," independent sanctions monitors reported to the UN Security Council North Korea sanctions committee.
"The DPRK continued to develop its capability for the production of fissile material at the Yongbyon site," the monitors wrote, referring to North Korea's formal name - the Democratic People's Republic of Korea.
Yongbyon is North Korea's major nuclear facility, operating its first nuclear reactors.
North Korea's UN mission in New York did not immediately respond to a request for comment on the report.
The United States has long been warning that North Korea is ready to carry out a seventh nuclear test and says it will again push to strengthen UN sanctions on Pyongyang if it takes place.
The UN monitors also said investigations had shown Pyongyang was to blame for stealing hundreds of millions of dollars worth of crypto assets in at least one major hack. The monitors have previously accused North Korea of carrying out cyber attacks to fund its nuclear and missile programs.
"Other cyber activity focusing on stealing information and more traditional means of obtaining information and materials of value to DPRK's prohibited programmes, including WMD (weapons of mass destruction), continued," the monitors wrote.
North Korea has for years been banned from conducting nuclear tests and ballistic missile launches by the UN Security Council, which has strengthened sanctions on Pyongyang over the years to try and cut off funding for those programs.
"DPRK made preparations at its nuclear test site, although it did not test a nuclear device. In the first half of 2022, the country continued the acceleration (which began in September 2021) of its missile programmes," the monitors said.
They said North Korea launched 31 missiles combining ballistic and guidance technologies, including six intercontinental ballistic missiles (ICBM) tests and two missiles that it explicitly described as ballistic weapons.
North Korea continued illicit imports of oil and exports of coal, evading sanctions, the monitors said.
International talks aimed at convincing North Korea to give up its nuclear and ballistic missile programs have largely stalled since 2019.
In recent years China and Russia have been pushing for an easing of sanctions on North Korea on humanitarian grounds –– and in the hope, that Pyongyang can be convinced to return to negotiations.
The UN monitors reported that while challenging to assess accurately, "there can be little doubt that UN sanctions have unintentionally affected the humanitarian situation" in North Korea.