“We don’t really see any kind of limitation on whatever type of ship could pass through those waters,” Admiral John Richardson told reporters in Tokyo, when asked if more advanced Chinese weapons posed too great a risk.

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“We see the Taiwan Strait as another [stretch of] international waters, so that’s why we do the transits.”

Aircraft carriers, typically equipped with about 80 aircraft and crews of about 5,000, are key to the US military’s ability to project power globally.

The comments follow increasing cross-strait tensions in which Beijing’s renewed push for Chinese reunification has seen it adopting more aggressive stance.

In response to this Taipei and Washington have been moving closer together.

Earlier this month President Xi Jinping reiterated that China would not rule out the use of force and insisted the island must eventually be reunited with the mainland.

He also said Beijing “reserves the option of taking all necessary measures” against external forces that intervene to prevent peaceful reunification.

In October, Xi ordered the military region responsible for monitoring the South China Sea and Taiwan to “prepare for fighting a war”.

The island’s President Tsai Ing-wen has called for international support in defending Taiwan’s democracy.

On Tuesday, a US official said the United States was closely watching Chinese intentions toward Taiwan as advances in military technology give Beijing’s forces greater capability to occupy the island.

In a report, the US Defence Intelligence Agency called Taiwan the “primary driver” for China’s military modernisation.

Richardson, who visited China before travelling to Japan, said he told his Chinese counterparts the United States was opposed to any unilateral action by Beijing or Taipei.

He also urged China to stick to international rules during unplanned naval encounters at sea.

That request came after a Chinese destroyer approached the USS Decatur in October and forced it to change course as it challenged Chinese territorial claims in the contested South China Sea with a freedom of navigation operation.

“We have made this very clear that this was an excursion, a departure from the normal adherence to those rules and we would hope that behaviour in the future would be much more consistent,” Richardson said.

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“We should not see each other as a threatening presence in these waters.”

The US Navy continues to pass through waters in the South China Sea that Beijing considers its territory.

On January 7, a US guided-missile destroyer sailed within 12 miles of a Chinese-occupied island, prompting Beijing’s rebuke that it had “gravely infringed upon China’s sovereignty”.

Mainland China, which claims almost all of the strategic waterway, says its intentions are peaceful. Brunei, Indonesia, Malaysia, the Philippines, Taiwan and Vietnam have competing claims.

Analysts noted that the more assertive stances both US and China have adopted on Taiwan were likely to spill over into other areas.

James Floyd Downes, a lecturer in comparative politics at the Chinese University of Hong Kong, said the “Taiwan issue is likely to act as a major barrier between the two countries and stop them ultimately from working together … A clash is very much on the horizon in the future between China and the US.”

Downes also argued that their disagreements on Taiwan were likely to affect their stance on other areas such as the economy and the ongoing trade war.

“This could also have a detrimental effect on the global economy if the chill in relations continues,” Downes said.

Ryo Hinata-Yamaguchi, a visiting professor at Pusan National University in South Korea and adjunct fellow at the Pacific Forum, said Richardson’s comments were a clear signal from the US that it would not be intimated by China’s military advances.

“Both sides view one another as upsetting the status quo. The US is increasingly concerned about China’s posture toward Taiwan, and Washington’s response will certainly aggravate Beijing,” Ryo said.

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But observers said increasing tension did not necessarily mean there was an increased possibility of military conflict.

Zhang Baohui, a security analyst at Lingnan University in Hong Kong, stressed that increased US activity should be seen as a diplomatic ploy.

“US is well aware of the combustibility of this issue and would continue to handle it with care. I doubt the US has immediate plans to send an aircraft carrier through the Taiwan Strait,” he said.

Beijing and Washington agreed last year to create a crisis communication and deconfliction mechanism to avoid unwanted military conflicts.

“The Trump administration has been talking about this possibility [of sending a carrier through the strait] for a while but has not done anything,” Zhang said.

“Both sides are aware of the dangers of war between them. This should serve to moderate US behaviour toward the Taiwan Strait.”