Xi Jinping has told a gathering of Communist Party officials that China must modernise its military, oppose Taiwan pro-independence forces and promote "reunification of the motherland".
Speaking at the National Peoples' Congress (NPC), China's ceremonial parliament, Mr Xi said his country must turn its military into a "Great Wall of Steel" that would safeguard his country's sovereignty, security and developmental interests.
Mr Xi was on Friday crowned one of modern China's most powerful leaders in generations after being handed a historic third term as president.
"Security is the foundation for development, stability is the prerequisite for prosperity," he said in his address at the closing of the NPC in Beijing.
In his first speech since becoming leader for a third term, Mr Xi said his country must achieve greater self-reliance and strength in science and technology, and promote industrial transformation.
The United States imposed control measures in October last year aimed at blocking China's access to chip-making equipment and other technologies.
Mr Xi said China should oppose interference from external forces on Taiwan and that Beijing should actively promote the peaceful development of cross-strait relations.
Beijing should "fully, faithfully and firmly" implement the one country, two systems doctrine to ensure long-term prosperity and stability in Hong Kong and Macau, he said, amid recent protests in the special administrative region.
He said China should bolster efforts to upgrade and expand the economy, increase the country's economic strength, and scientific and technological capabilities.
"The great rejuvenation of the Chinese nation has entered an irreversible historical process," he said.
New Premier Li Qiang criticises US 'encirclement'
Li Qiang delivered his first press conference after being appointed China's new premier at the NPC on the weekend.
Mr Li, 63, replaces Li Keqiang, and becomes the second-most senior leader in China after Mr Xi, joining the seven member Standing Committee of the Politburo.
He criticised the United States for what he said amounted to "encirclement and suppression", as relations between the two superpowers worsen.
"China and the United States should cooperate, and must cooperate. When China and the US work together, there is much we can achieve," Mr Li said.
Mr Li is a close ally of Mr Xi and was previously Communist party secretary of Shanghai.
He famously enforced a hardline "zero-COVID" policy in the city in 2022 which endured a two-month lockdown.
It triggered protests over residents' access to food, medical care and basic services.
He said achieving China's annual growth target of 5 per cent — one of the lowest targets in decades — would be "no easy task" and would require Beijing to "redouble" efforts.
China recorded 3 per cent growth last year, falling well short of its growth target of 5.5 per cent as its economy suffered under the impact of its COVID-19 containment policies.
Mr Li said China still remained a global investment "highland" and was firmly committed to opening up regardless of how the external situation changed.
China would further open its doors and improve its business climate and services, Mr Li said.
The premier said Beijing would maintain a zero-tolerance policy for corruption, despite examples of corruption surfacing, including after an attack on restaurant patrons in Tangshan, Hebei province last year.
