It comes as the US plans another round of economic sanctions against North Korea

Kim Jong Un's sister is set to attend the opening ceremony of the Winter Olympics in South Korea this week.

Seoul officials confirmed that Kim Yo Jong - the youngest daughter of the late Kim Jong Il - will attend Friday's event.

She is said to be closer to her older borther, and is also an alternate member of North Korea's top decision-making body, the politburo.

The games in Pyeongchang will see North and South Korean athletes marching under the same banner at the opening ceremony, while there will also be a single united Korean ice hockey team.

A delegation of North Korean athletes will also compete in several events, including cross-country skiing, figure skating and short-track speed skating.

It comes as the US announced plans for fresh economic sanctions yet against North Korea.

Vice President Mike Pence, who is currently in Japan, said: "The United States of America will soon unveil the toughest and most aggressive round of economic sanctions on North Korea ever - and we will continue to isolate North Korea until it abandons its nuclear and ballistic missile programs once and for all."

He also warned that the North & South Korea had previously "marched under the same banner" at past Olympics "only to see North Korea continue its pursuit of threats and provocations".