Covid-19 restrictions may be playing a role in North Korea's lack of response to offers of diplomatic talks, a senior US administration official said on Sunday, a day after President Joe Biden said he had offered vaccines to Pyongyang.

Biden is in South Korea before heading to Japan later on Sunday as part of his first trip through Asia as president.

Meeting with recently elected South Korean President Yoon Suk-yeol on Saturday, Biden vowed to step up efforts to deter North Korean threats but also said he was open to talks - including sitting down with leader Kim Jong Un (above) if necessary - and that he had offered Covid vaccines to Pyongyang with no response.

North Korea has said...