Prospects for progress in global nonproliferation efforts are not bright due to North Korea's continued pursuit of its nuclear program, the U.S. think tank Council on Foreign Relations said Tuesday.

In a report on global cooperation, the CFR said that global nonproliferation efforts received a boost from the Iranian nuclear deal last year, but suffered a setback from the North's nuclear program.

"North Korea continued to threaten the international nonproliferation regime and global peace and stability through its pursuit of nuclear weapons and delivery vehicles," the report said.

The North is believed to have restarted its uranium enrichment and plutonium production at the Yongbyon complex in September 2015, and improved its uranium mining and milling capacity. However, the six-party nuclear talks remain dead since they stalled in 2008, the report said.

Pyongyang also claimed it tested a submarine-launched ballistic missile in May 2015, the report said.

"Past efforts to restrain North Korea's nuclear program have been unsuccessful, and if this renewed bellicosity goes unanswered, it could embolden the Democratic People's Republic of Korea to accelerate its nuclear weapons program," it said. "Thus, the Council on Foreign Relations was not optimistic about significant progress in combating nuclear proliferation in 2016." (Yonhap)