BEIJING: Celebrations in Beijing to mark the 100th anniversary of the founding of China's ruling Communist Party kicked off on Thursday morning with a flyby of fighter jets and helicopters at Tiananmen Square in the centre of the capital.

Around 30 aircraft formed a "100" as crowds cheered under the gaze of the nation's leaders, including President Xi Jinping, seated at the southern ramparts of the Forbidden City.

In a televised address from the square, Xi said China had achieved its centenary goal of building "a moderately prosperous society."

The overarching theme of the party's work over the past 100 years was to rejuvenate the nation, said Xi, China's most powerful leader since Mao Zedong.

"The people of China are not only good at destroying the old world, they have also created a new world," Xi said. "Only socialism can save China."

Xi and the party are riding high as China recovers briskly from the COVID-19 outbreak and takes a more assertive stand on the global stage, although Beijing also faces criticism over its actions in Hong Kong and Xinjiang, and contends with a worsening demographic outlook that imperils long-term economic growth.

The people of China would never allow any foreign force to bully, oppress, or subjugate them, Xi said.

"Anyone who dares try to do that will have their heads bashed bloodied against the Great Wall of Steel forged by over 1.4 billion Chinese people," he said.

The Chinese Communist Party, which came to power in 1949 under Mao, initially recruited peasants and workers, but has evolved to embrace markets and entrepreneurship under "socialism with Chinese characteristics" while retaining a Leninist model of authoritarianism.

China will build up its military to safeguard its sovereignty, security and development, elevating it to world-class standards, Xi said in his address on Thursday.

"We must accelerate the modernisation of national defense and the armed forces," said Xi, who is also chairman of the Central Military Commission, which controls the country's armed forces.

Party ranks swelled by 2.43 million in 2020, the largest annual gain since Xi became president in 2013, to 95.15 million members now, data released on Wednesday showed.

On Monday, Xi presided over theatrical performances at the "Bird's Nest" National Stadium in a show attended by thousands and that state media described as "epic".

At the end, the audience rose to sing a song, "Without the Communist Party, There Would Be No New China."

Xi said any attempt to divide the party from the Chinese people or to set the people against the party was bound to fail.

"The more than 95 million party members and the more than 1.4 billion Chinese people will never allow such a scenario to come to pass," Xi said.