The Australian defense minister says his country has made no promises to the United States that Australia would support its ally in any future conflict over Taiwan in exchange for American nuclear-powered submarines.

U.S. President Joe Biden and the leaders of Australia and the United Kingdom announced in San Diego last week that Australia would purchase nuclear-powered attack submarines from the U.S. to modernize its fleet amid growing concern about China’s influence in the Indo-Pacific.

Australian critics of the deal argue that the United States would not hand over as many as five of its Virginia-class submarines without assurances that they would be made available in the event of a conflict with China over Taiwan. Beijing says the self-ruled island democracy, which split with China in 1949 after a civil war, is obliged to unite with the mainland, by force if necessary.

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But Defense Minister Richard Marles said his government had given the United States no assurances over Taiwan.

“Absolutely not, and I couldn’t be more unequivocal than that,” Marles told Australian Broadcasting Corp. ’s “Insiders” news program on Sunday.

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“I want to make it really clear that the moment that there is a flag on the first of those Virginia-class submarines in the early 2030s is the moment that that submarine will be under the complete control of the Australian government of the day and again, no one would have expected that to be any different. I mean, that is obviously the basis upon which this is happening,” he added.

Australia, like the United States, has a policy of “strategic ambiguity" in refusing to say how it would react to a Chinese attack on Taiwan. Australia and the U.S. have also shared a bilateral defense treaty since 1951 that obliges them to consult if either comes under attack but does not commit them to the other's defense.

Former Australian Prime Ministers Paul Keating and Malcolm Turnbull are among the critics who question how Australia could maintain its sovereignty with such heavy reliance on U.S. technology and military personnel under the submarine deal.

The AUKUS deal — named after Australia, the United Kingdom and the United States — provoked an angry reaction from China, which accused Australia of going down a “path of error and danger."

Marles said while the submarines could be used in the case of a conflict, the main intention was for them to protect vital trade routes through the South China Sea and contribute to regional stability.

“Nuclear-powered submarines have obviously the capacity to operate in the context of war, but the primary intent here is to make our contribution to the stability of the region,” Marles said.