Increasingly tough financial sanctions, an arms embargo and other international restrictions on trade with North Korea have significantly delayed expansion of Pyongyang’s illicit nuclear arms program, according to a confidential report by a UN panel of experts seen by Reuters.

The latest annual report by the UN sanctions-monitoring group comes as the US seeks to convince China that applying economic and other sanctions against its neighbour is crucial to halting the programme.

“While the imposition of sanctions has not halted the development of nuclear and ballistic missile programs, it has in all likelihood considerably delayed (North Korea’s) timetable and, through the imposition of financial sanctions and the bans on the trade in weapons, has choked off significant funding which would have been channeled into its prohibited activities,” the group said in a 52-page report.

The document covers the period up through last month, diplomats said, so it was too early to measure the effect of the latest round of UN sanctions adopted in March.

In the report to the UN Security Council’s North Korea sanctions committee, the panel also recommended sanctioning three North Korean entities and 12 individuals. It will be up to the 15-nation council whether or not it follows the recommendations.

The three entities the panel said should be blacklisted are the newly created Ministry of Atomic Energy Industry, the Munitions Industry Department of the Central Committee of the Korean Workers Party (KWP), and the State Space Development Bureau.