PYEONGCHANG, SOUTH KOREA (AFP, REUTERS) - Athletes from South and North Korea marched behind the blue-and-white Korean unification flag at the opening ceremony for the Pyeongchang Winter Olympics on Friday (Feb 9) to huge cheers.

Won Yun Jong, a bobsledder from the South, and North Korea's Hwang Chung Gum, who will play for the joint Korean women's ice hockey team, led out the contingent at the Olympic Stadium.

Everyone in the stadium took to their feet when the North and South Korean athletes marched out under a unified flag, CNN reporter Paula Hancocks tweeted.

"It was incredible," spectator Eim Young Joo said.

North Korean cheerleaders greeted the athletes by waving a controversial version of the flag depicting disputed islands known as Dokdo in Korean and Takeshima in Japanese.

The "Peace Olympics" got underway in a spirit of high rapprochement with the arrival of Kim Yo Jong, the sister of North Korean leader Kim Jong Un, forming part of the North's most high-ranking delegation ever seen in the South.

President Moon Jae In, who wants to harness the Olympic spirit to pave the way for talks over the North's weapons programme, warmly shook hands with her as well as the North's nominal head of state Kim Yong Nam.

The South is still technically at war with the North after the 1950-53 Korean War ended in a truce, and the United States and North Korea have recently swopped nuclear threats. US Vice-President Mike Pence, who was seated near to the North Korean representatives at the opening ceremony, vowed only this week to tighten sanctions on the North.

Underlining Moon's efforts to re-engage with the North, the opening ceremony followed the storyline of children wandering through a mythical landscape and discovering a world where people live in peace and harmony.

International Olympic Committee President Thomas Bach told the crowd that by allowing their athletes to march together under one flag at the ceremony, North and South Korea had shown sport's "unique power" to unite people.

"All the athletes around me, all the spectators here in the stadium, and all Olympic fans watching around the world... we are all touched by this wonderful gesture," he said.

The Olympics have provided some respite from years of tense relations between Seoul and Pyongyang, though just hours before the ceremony hundreds of anti-North Korean protesters scuffled with riot police outside the stadium, burning North Korean flags and pictures of its leader, Kim Jong Un.

Both Koreas marched together at the 2000 Sydney Games' opening ceremony and have competed as a single nation in international table tennis and football matches. They have never joined forces at the Olympics or Asian Games.

North Korea participated in international multi-sports events hosted by South Korea three times - the 2002 Busan Asian Games, the 2003 Summer Universiade in Daegu and the 2014 Incheon Asiad.

South Korea's frigid February, where temperatures have plummeted to minus 20 deg C at night, has come as a shock to the system for athletes and visitors alike in the lead-up to these Games, prompting concerns about hypothermia at the opening ceremony.

The weather was a little milder than feared on Friday, but spectators still huddled near heaters, holding hot packs and slurping down steaming fishcake soup to ward off the chills.

Bundled up in a scarf, mask and knitted hat, with hot packs tucked into her knee blanket, office worker Shin Hye Sook said she and her three colleagues were coping with the cold. "We're sitting as close as we can and trying not to move a lot to save our energy," said the 60-year-old.

The alpine town first bid for the 2010 Games but narrowly lost out to Vancouver, and suffered similar heartbreak when it was beaten to the 2014 Olympics by Sochi.

After announcing its arrival on the international stage by hosting the 1988 Seoul Olympics, South Korea now wants to show the world just how far it has come over the last 30 years with a Games showcasing its culture and technological prowess.

According to Olympic tradition, the Greek contingent headed the parade of athletes into the open-air stadium, followed by the other delegations in order according to the Korean alphabet.

Pence stood to welcome the US athletes as the Korean pop hit Gangnam Style blared around the stadium, sparking the "Horse Dance" in the crowd and among the volunteers.

The moment failed to elicit even a smile from the two senior North Korean officials in the VIPs box, however, as they sat stony-faced in black fluffy hats and long coats.

As the ceremony neared an end, the Olympic flame was carried by a succession of Korean sporting heroes including 2016 Rio Games golf champion Park In Bee and soccer player Ahn Jung Hwan, who scored the winning goal against Italy at the 2002 World Cup.

It finally found its way to figure skating star Kim Yuna, who won gold at the 2010 Vancouver Games and silver in Sochi four years later.