A former national security adviser to Donald Trump slammed Joe Biden’s foreign policy, saying North Korea is a year closer in perfecting its nuclear and ballistic missile technology as a result of Biden’s diplomacy on Pyongyang -- or lack thereof.

In an op-ed published by Washington-based news outlet the Hill on Sunday, John Bolton identified Iran and North Korea as the Biden administration’s nuclear proliferation failures in 2021.

Bolton, who championed a hawkish policy toward Iran and North Korea, said that while both Tehran and Pyongyang want Washington to release economic pressure on them, neither want it enough to “make the strategic decision to abandon pursuing deliverable nuclear weapons.”

“After a year of frenetic diplomacy and public optimism on Iran, and a year of frenetically doing essentially nothing on North Korea, the result in both cases is identical. Tehran and Pyongyang are one year closer to perfecting their nuclear and ballistic-missile technology, and for North Korea perhaps hypersonic cruise missiles,” Bolton said.

“Time is always on asset for the proliferator, needed to overcome the complex scientific and technological obstacles to becoming a nuclear-weapons state,” he said, adding both Iran and North Korea have made good use of 2021, while the US stood idly by.

Since Biden took office last January, Washington has consistently called on Pyongyang to engage in dialogue for denuclearization. But the North has reiterated that it will ignore the offer of dialogue, unless the US rolls back what it calls a “hostile policy” toward the North -- apparently referring to the joint military exercises between South Korea and the US, and international sanctions.

In the meantime, Pyongyang continued to beef up weapons capabilities throughout the year despite UN Security Council sanctions and repeated calls for engagement from Seoul and Washington. Last year, it tested a new submarine-launched ballistic missile, a long-range cruise missile, a train-launched ballistic missile and a hypersonic missile, among others.

While Pyongyang has kept its provocation and testing below the alarming level of nuclear and long-range ballistic missiles, observers say the regime could break its self-imposed moratorium on ICBMs and nuclear tests this year to gain leverage with Washington.