Washington - The United States, responding to remarks made by Cambodian Prime Minister Hun Sen earlier in the week, said on Tuesday that the trilateral security alliance between Australia, the United Kingdom and the United States is not an effort to spread nuclear weapons in Southeast Asia and the Indo-Pacific region.

On Monday, Hun Sen said that the trilateral group known as AUKUS was 'the starting point of a very dangerous arms race' as he objected to the coming of nuclear-powered submarines to the region.

The three allies signed a deal in March to strengthen their presence in the Asia-Pacific region where China is expanding its military stance. The agreement calls for Australia to buy three nuclear-powered submarines from the United States.

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'AUKUS is intended to enhance peace, prosperity, security, and stability in the Indo-Pacific and beyond. Through AUKUS we will support Australia's acquisition of conventionally armed, nuclear-powered submarines - a proven and safe technology,' a State Department spokesperson said on Tuesday in an email response to VOA's request for comments.

Hun Sen said the Association of Southeast Asian Nations, or ASEAN, is 'a nuclear weapon-free zone,' a regional bloc that opposes nuclear weapon proliferation. AUKUS, he said, is the 'starting point of a very dangerous arms race.'

'The small-scale alliance relevant to nuclear-powered submarines among the U.S., Britain and Australia is becoming a concern for ASEAN and countries in the region,' Hun Sen said at a graduation ceremony in Cambodia's capital, Phnom Penh, on Monday.

China, which is ASEAN's comprehensive strategic partner while being at odds with ASEAN member nations over territorial claims to the South China Sea, expressed support for Hun Sen's statement on AUKUS and for a nuclear weapon-free Southeast Asia.

Five members oppose China's claims

ASEAN members are Brunei, Cambodia, Indonesia, Laos, Malaysia, Myanmar, the Philippines, Singapore, Thailand, and Vietnam. Five - Brunei, Indonesia, Malaysia, the Philippines and Vietnam -oppose China's claims in the South China Sea, waters rich in natural resources where China has expanded aggressively by building islands for military and tourism use.

Chinese Foreign Ministry spokesperson Wang Wenbin said at the regular daily press briefing on Tuesday that 'according to estimates by international arms control experts, the amount of weapon-grade nuclear materials the U.S. and the U.K. will give to Australia could be used to manufacture up to 64 to 80 nuclear weapons.'

Wang added that Hun Sen's remarks speak to concerns widely shared by regional countries, including the ASEAN nations, according to China's official Xinhua news outlet.

'If the three countries are set on advancing their nuclear submarine cooperation, it is bound to deal an irreversible heavy blow to the integrity, efficacy and authority of the international nuclear non-proliferation system and trigger similar behavior in other non-nuclear-weapon states, thus turning the region into an arena of arms race,' said Wang.

'Commitment to nuclear nonproliferation'

A U.S. State Department spokesperson told VOA Khmer that AUKUS does not aim to equip Australia with nuclear weapons and the partnership 'is possible because of Australia's long-standing and demonstrated commitment to nuclear nonproliferation.'

'To be clear, Australia does not, and will not, seek nuclear weapons and remains committed to its international non-proliferation obligations,' said the State Department spokesperson.

The State Department also noted that 'AUKUS stands in sharp contrast to others in the region that continue to invest heavily in building up military capabilities while offering little transparency or reassurance.'

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President Joe Biden has promised to double down on U.S. ties with Southeast Asia, but the U.S. has sanctioned key Hun Sen allies and objected to moves that limit democracy and press freedom.

But the U.S. is a crucial export market for Cambodia, and despite its tough talk about U.S. interference in its affairs, Phnom Penh has indicated a desire to mend fences. Since 2019, the Cambodian government has hired at least three U.S.-based lobbying firms in an effort to improve ties with Washington and attract American investment.