PYEONGCHANG, South Korea — The opening ceremony of the 23rd Winter Olympics unfurled in frigid temperatures and high spirits on Friday, as athletes from the two Koreas marched into the stadium together less than 50 miles from the heavily-fortified border between their nations, offering hope of a breakthrough in a tense, geopolitical standoff that has stirred fears of nuclear conflict.

The festivities started what organizers say is the largest Winter Olympics yet, with 92 countries participating. The North and South Korean delegations, marching under one flag, embodied the hopes of a peninsula divided by history and ideology.

Whereas recent Olympic Games have sought to set politics to one side, the strategic subtext of the event in Pyeongchang this year has been unavoidable.

Kim Yo-jong, the younger sister of Kim Jong-un, North Korea's leader, was sitting at the opening ceremony closely behind Vice President Mike Pence, who led the American delegation. Also present was the father of Otto Warmbier, the American student who was jailed in North Korea last year, returned home in a coma and died shortly afterward.

Earlier in the week, the United States warned against a North Korean charm offensive and announced plans to impose its toughest sanctions yet against Pyongyang, which staged a military parade featuring ICBMs just a day before the Games opened.

The mounting political drama loomed over other Olympic story lines, including the participation of Russian athletes despite a ban after a doping scandal, and the appearance of the first Nigerian contingent in the Winter Games with a women's bobsled team. And then there are the gold medal hopefuls, like Nathan Chen, the American ice skating prodigy who may seek to land five quad jumps in competition, and Chloe Kim, the teenage Korean-American snowboarding phenom.

And as if there were not enough distractions already, a worsening outbreak of the highly contagious norovirus has been spreading from security personnel to other Olympic workers.