Beijing announced the trial on Wednesday -- its first such test in four decades -- saying that the missile was carrying a dummy warhead.

The launch sparked protests from countries in the region, with China's neighbour Japan saying it had not been given advance notice and Taiwan expressing "solemn condemnation".

Beijing's defence ministry said on Thursday the test was "a legitimate and routine arrangement" that aimed to "test our weapon and training performance".

"China's nuclear policy is very stable, consistent and predictable," ministry spokesman Zhang Xiaogang told a news conference in Beijing.

"We strictly follow a nuclear policy of no first use of nuclear weapons and pursue a nuclear strategy of self-defence," he said.

He said China does not seek an "arms race" and had "promised not to use or threaten to use nuclear weapons against non-nuclear weapons states or weapon-free zones".

"China will continue to keep its nuclear capabilities at the minimum level required for national security," Zhang said.

- International outcry -

Japan said it had not been given advance warning of the launch. Taiwan, the self-ruled island that Beijing claims as its territory, expressed "solemn condemnation".

Australia said it was seeking "an explanation", while New Zealand called the launch "an unwelcome and concerning development".

French Polynesia President Moetai Brotherson said "the missile fell not far from... the Marquesas Islands", an archipelago that is part of its exclusive economic zone.

"The Chinese authorities previously notified their French counterparts of this test," the French High Commission said in a statement, adding that France would make its position on the test known.

The Pentagon also said the United States received "some advanced notification of this ICBM test", describing the notification as "a step in the right direction" that would help prevent "misperception or miscalculation".

China's military released imagery of the missile on Thursday that showed the projectile soaring into the air in a plume of smoke from an undisclosed location.

Analysts said the imagery suggested the launch could be of a Dongfeng-31 AG intercontinental ballistic missile, unveiled during a military parade in 2017.

- Growing arsenal -

Beijing has stepped up its nuclear development and boosted defence spending in recent years.

The Pentagon warned last October that China was developing its arsenal more quickly than the United States had anticipated.

China held more than 500 operational nuclear warheads as of May 2023 and is likely to have more than 1,000 by 2030, the Pentagon said.

One analyst told AFP Beijing was "clearly trying to... signal that 'we are strong'".

"It sends a signal to the US and its allies... that China has the military ability to react in the event of any escalation of tensions between the United States and China," said Benjamin Ho, assistant professor at Singapore's S. Rajaratnam School of International Studies' China Programme.

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