Russian President Vladimir Putin and Chinese President Xi Jinping unveiled a global alliance with an anti-Western tilt on Friday, just hours before the grand opening of the Olympics in Beijing, in a striking juxtaposition of politics and sport.

Xi later kicked off the opening ceremony, joined by International Olympic Committee Chairman Thomas Bach as he entered Beijing's famed Bird Nest stadium, its rim decked with the flags of the 91 countries and regions taking part.

The event was to feature 3,000 performers on a stage comprised of 11,600 square metres of high-definition LED screen resembling an ice surface.

The crowd was pared down, with organisers deciding last month not to sell tickets to Olympic events to curtail the spread of Covid-19. A "closed loop" separates competitors and other personnel from the Chinese public throughout the Olympics.

Using the day to announce the new Russian-Chinese alliance was an extraordinary reminder that the games were taking place on a backdrop of geopolitical rivalry unseen since the 1980s - when the United States boycotted games in Moscow and the Soviet Union stayed away from Los Angeles four years later.

With geopolitical tensions on both sides of the Eurasian land mass at their most taut for decades, Putin and Xi publicly took each other's sides in a range of disputes, notably Ukraine, where the West accuses Putin of preparing for war.

The lengthy joint statement released after their meeting occasionally veered into Cold War-era rhetoric, condemning "certain states' attempts to impose their own 'democratic standards' on other countries".

"Such attempts at hegemony pose serious threats to global and regional peace and stability and undermine the stability of the world order," they said.

Diplomatic boycott

The United States and other countries have declined to send dignitaries to Beijing, citing alleged human rights abuses, which Beijing denies.

China's role in international sport has also drawn other uncomfortable headlines in recent months, with the women's tennis tour cancelling events there over the case of Peng Shuai, a tennis player who appeared to vanish after accusing a senior official of sexual assault. Chinese media have shown Peng making public appearances, including a video phone call last year with Olympics boss Bach.

"I would like to thank you for the invitation to the opening of the Olympic Games," Putin told Xi. "We know firsthand that this is a huge job. I am sure that our Chinese friends have done it brilliantly, as you always do when preparing such major events."

In Putin and Xi's joint statement, China backed Russia's longstanding call for NATO to halt its expansion - Moscow's central demand in a dispute with Western countries that say they believe Putin is preparing for war in Ukraine.

Russia, which has deployed more than 100,000 troops to the Ukrainian frontier, denies planning to invade but says it could take unspecified military action unless demands are met, including barring Ukraine from ever joining NATO.

Moscow, for its part, said it fully supported Beijing's stance on Taiwan and opposed Taiwanese independence in any form.

A broadcast aired in Moscow showed Xi and Putin, neither wearing a mask, sitting opposite each across a large table in a Beijing state guesthouse, surrounded by masked aides.

"I am ready to work with President Putin to plan the blueprint and steer the course for Sino-Russian relations under new historical conditions,” Xinhua quoted Xi as saying.

China state television footage showed a jet flying with the Russian and Chinese flags. Next to it were jets with Mongolian and Serbian flags. Serbian president Aleksandar Vucic and Prime Minister L. Oyun-Erdene of Mongolia were expected to attend the opening ceremony later on Friday.

Qatar's Emir Sheikh Tamim bin Hamad Al Thani and the United Arab Emirates' Crown Prince Sheikh Mohamed bin Zayed Al Nahyan had also touched down, according to state media reports.

Before this week, Beijing had not received foreign political guests for almost two years as it tried to keep the coronavirus out.