North Korea unresponsive to behind-the-scenes Biden administration outreach - US official

North Korea has not responded to behind-the-scenes diplomatic outreach since mid-February by President Joe Biden's administration, including to Pyongyang's mission to the United Nations, a senior Biden administration official told Reuters on Saturday.

The disclosure of the so-far unsuccessful US outreach, which has not been previously reported, raises questions about how Biden will address mounting tensions with Pyongyang over its nuclear weapons and ballistic missile programs.

It also adds a new dimension to a visit America's top diplomat and defense secretary will make next week to South Korea and Japan, where concerns over North Korea's nuclear arsenal are expected to be high on the agenda.

The senior Biden administration official, speaking on condition of anonymity, offered few details on the diplomatic push. But the official said there had been efforts to reach out to the North Korean government "through several channels starting in mid-February, including in New York."

"To date, we have not received any response from Pyongyang," the official said.

North Korea's mission to the United Nations did not immediately respond to a request for comment.

The Biden administration has so far been cautious in publicly describing its approach to North Korea, saying it is carrying out a comprehensive policy review following former President Donald Trump's unprecedented engagement with North Korean leader Kim Jong Un.

Trump's efforts failed to persuade North Korea to give up its nuclear weapons.

The Biden administration official said it appeared there had been no active dialogue between the United States and North Korea for more than a year, including at the end of Trump's administration, "despite multiple attempts during that time by the United States to engage."

The US official declined to speculate about how the silence from Pyongyang would impact the Biden administration's North Korea policy review, which was expected to be completed in the coming weeks.

During his election campaign, Biden described Kim as a "thug" and said he would only meet him "on the condition that he would agree that he would be drawing down his nuclear capacity."

US Secretary of State Antony Blinken has held out the possibility of additional sanctions, in coordination with allies, to press North Korea to denuclearize.

Sanctions have so far failed to convince Kim to give up his nuclear weapons.

Blinken is slated to host the first face-to-face discussions between senior Biden administration and Chinese officials on March 18 in Alaska. The Trump administration accused China of failing to enforce sanctions against North Korea. A confidential U.N. report here found that North Korea maintained and developed its nuclear and ballistic missile programs throughout 2020 in violation of international sanctions, helping fund them with some $300 million stolen through cyber hacks.

The report by independent sanctions monitors said Pyongyang "produced fissile material, maintained nuclear facilities and upgraded its ballistic missile infrastructure" while continuing to seek material and technology for those programs from abroad.