Italy launched the Milano Cortina Winter Olympics with a slick and colourful ceremony that celebrated the country's history, arts and fashion but where global political tensions surfaced in the crowd reaction.

Italian President Sergio Mattarella formally declared the Games open at the main event in Milan's San Siro stadium as part of an unprecedented show that also linked to celebrations in co-host Cortina d'Ampezzo, more than 400 kilometres away in the Dolomites.

US Vice President JD Vance and Secretary of State Marco Rubio were among the crowd in the iconic football stadium for the performance entitled "Armonia" (Harmony) that lasted three and a half hours.

Vance, who has been strongly critical of Europe, drew jeers in the stadium when an image of him waving the US flag appeared on a big screen.

The announcement of the Israeli team prompted some booing in Milan over the loud soundtrack, but there were cheers in Cortina. Israel has a team of 10 in Italy.

The group of five athletes from Ukraine ‍in Milan drew huge cheers.

International Olympic Committee president Kirsty Coventry said the Games should bring people together. "This is the magic of the Olympic Games: inspiring us all to be the best that we can be – together," she added.

For ‍the first time, two Olympic cauldrons, one of the symbols of the Games, were lit simultaneously and will burn throughout – one at Milan's Arco della Pace (Peace Arch) and the other in Cortina's Piazza Dibona.

Alberto Tomba and Deborah Compagnoni, two of Italy's most successful Alpine skiers who both won three Olympic gold medals, lit the cauldron at the 19th century Milan monument.

Sofia Goggia, one of Italy’s top medal hopes for these Games, did the honours in Cortina. She became the first Italian woman to win an Olympic downhill gold at the 2018 edition.

US pop ‌star Mariah Carey had got the party started in a unique opening ceremony combining elements from the co-hosts, seeking to reflect both city and mountain life, performing the 1950s Italian song "Nel blu, dipinto di blu" ("In the blue, painted in blue") with its famous "Volare" ("To fly") ‍refrain to cheers in the stadium.

The show also included a tribute to the late Italian fashion designer Giorgio Armani, who made Milan his base and died in September.

The ceremony celebrated the diversity of Italian life, from fashionable Milan to the smaller mountain towns in the Alps that host the outdoor events at the Games, which run until February 22.

Athletes also paraded in the mountain venues of Livigno and Predazzo, in a Games spread over 22,000 square kilometres. (Reuters)