"We continue to assess that North Korea is unlikely to give up all of its nuclear weapons and production capabilities, even as it seeks to negotiate partial denuclearization steps to obtain key US and international concessions," Coats said in a report to Congress on threats to the United States.

"North Korea will continue its efforts to mitigate the effects of the US-led pressure campaign, most notably through diplomatic engagement, counterpressure against the sanctions regime, and direct sanctions evasion," Coats said in the report.

The report, an annual assessment of threats against the United States from the entire US intelligence community, said North Korea's leaders see having a nuclear weapons capability as "critical to regime survival."

It said Kim Jong Un, who is planning a second summit with Trump possibly in late February, is wooing China and South Korea to support its push for Washington to loosen sanctions pressure without making significant nuclear concessions.

"Kim has also sought to align the region against the US-led pressure campaign in order to gain incremental sanctions relief, and North Korean statements have repeatedly indicated that some sanctions relief is necessary for additional diplomacy to occur," the report said.