Pence could reinforce his influence during Asia-Pacific tour

US Vice-president Mike Pence begins a more than week-long tour of the Asia-Pacific and Hawaii on Sunday with a stop-off in Seoul followed by visits to Tokyo, Jakarta, Sydney and Honolulu. In a trip designed to underline continued US commitment to key Asia-Pacific alliances and partnerships, including the 40th anniversary of US-Asean relations, the No 1 item in the first half of the trip will be North Korea.

Last week, US President Donald Trump made clear prior to his meeting with Chinese President Xi Jinping that if Beijing "is not going to solve North Korea, we (the United States) will". This ups the ante from US Secretary of State Rex Tillerson's striking announcement last month that the two-decade-long US policy of "strategic patience" towards Pyongyang is now over and "all options" are on the table.

Last week's Xi-Trump meeting appears to have resolved little on North Korea, with both doing no more than treading water. After the session, Mr Trump called leaders in South Korea and Japan, while the USS Carl Vinson aircraft carrier was sent to waters near North Korea. Meanwhile, Mr Xi reportedly sent a Chinese envoy to South Korea.