US, North Korea set for uncomfortable encounter at Pyeongchang Olympics

North Korea's ceremonial leader and US Vice President Mike Pence are set for their first face-to-face encounter on Friday when they attend the opening ceremony of the Winter Olympics in Pyeongchang, South Korea.

Kim Yong Nam, North Korea's nominal head of state, is scheduled to land in South Korea along with leader Kim Jong Un's younger sister, Kim Yo Jong, aboard her brother's private jet at around 0430 GMT, according to Seoul's Unification Ministry.

Kim Yo Jong is the first member of North Korea's ruling family to visit the South, while Kim Yong Nam is the most senior North Korean official to make a cross-border trip.

They will have lunch with South Korean President Moon Jae-in on Saturday, Moon's office said.

Pence arrived in South Korea on Thursday and had talks and dinner with Moon, both reiterating their commitment and cooperation to defuse tensions on the Korean peninsula sparked by North Korea's missile and nuclear programmes.

He met North Korean defectors on Friday and was expected to pay tribute to a memorial for 46 South Korean sailors killed in 2010 in the sinking of a warship that Seoul blamed on a North Korean torpedo attack.

The move by Pence, who has described the North as the "most tyrannical and oppressive regime", is in line with Washington's campaign to put "maximum pressure" on Pyongyang.

Pence has kept open the possibility for some contact with the North Koreans in South Korea, while reiterating Washington's insistence that denuclearisation is a necessary condition for peace on the Korean peninsula.

Pence, Kim Yo Jong and other world leaders will attend the opening ceremony in the mountain resort of Pyeongchang, just 80 km (50 miles) from the heavily fortified border between North and South Korea, later on Friday.

Moon will also hold a welcoming reception for his top guests before the opening, a presidential official said, where Pence and Kim Yong Nam could sit at the same table with Moon.

South Korea is pinning its hopes on the Olympics as a venue to demonstrate its efforts to defuse tensions and foster inter-Korean rapprochement.

The Games will see athletes from the two Koreas march together under one peninsula flag for the first time in more than a decade.

Nearly 500 North Koreans are participating in the Olympics, which run through to Feb. 25, including a cheering squad, art troupe and taekwondo demonstration team, the South's Unification Ministry said.

But the inter-Korean Olympics detente has raised concerns in Washington and Tokyo that Seoul may undermine the US-led campaign of global pressure to get Pyongyang to abandon its nuclear and missile programmes.

Moon is also scheduled to hold a summit with Japanese Prime Minister Shinzo Abe, during which they are expected to discuss the North Korea standoff and the sensitive issue of "comfort women", a euphemism for girls and women forced to work in Japan's wartime brothels.

Abe said before leaving for the Olympics he wanted to convey to the world that cooperation among the United States, Japan and South Korea on the North Korean threat "will not waver".