A US government proposal to lease millions of hectares of seabed near the Mariana Trench for deep-sea exploration has faced opposition from US territories in the Pacific, as the Trump administration competes with China for access to critical ocean minerals, The Guardian reported on Monday.

Last week on Tuesday, the Marine Mineral Administration (MMA), an agency within the US Department of the Interior, announced plans to auction deep-sea mining leases covering 28 million hectares (69 million acres) of seafloor off the coasts of the Northern Mariana Islands and Guam.

The leases would permit companies to explore the seabed and potentially recover deposits of critical minerals known as polymetallic nodules. The minerals could be used in batteries, electronics and defense technologies. Environmental groups have broadly opposed deep-sea mining, arguing that further research is needed to understand its impact on marine ecosystems.

Northern Mariana Islands calls for caution

The Northern Mariana Islands is a self-governing commonwealth of the United States, while Guam is an unincorporated US territory.

David Apatang, governor of the Northern Mariana Islands, said his government would approach the Trump administration's proposal “with extreme caution”.

Apatang acknowledged the strategic significance of critical minerals but said, “no activity, survey or otherwise, takes place without rigorous scientific baseline studies, complete transparency, and explicit protections for our marine resources”.

He added that his administration would “thoroughly examine the proposed terms over the next 60 days to ensure that the ecological integrity of our waters and the long-term wellbeing of the [Northern Marianas] are fully safeguarded”.

The MMA told The Guardian in an earlier statement that it had completed an environmental review of proposed commercial leases for critical minerals in the Marianas region. The agency said it would take the governor's comments into consideration.

Guam rejects deep-sea mining efforts

A statement from the office of Guam's governor recognized the Trump administration's emphasis on national security and strategic requirements but warned, “National security cannot mean asking the people of the Pacific to accept environmental risks before those risks are fully understood.

Guam's lieutenant governor, Joshua Tenorio, said: "We’re unequivocally opposed to the deep-sea mining efforts in this region".

Tenorio told the Guardian, “The Department of Interior is giving assurances that mining activity is not going to commence with the awarding of these licences, [but] I think that this is a matter where we can’t really trust that because this has been rapidly evolving".

American Samoa also opposes seabed mining

The proposed notice for deep-sea exploration leases in the Marianas came only weeks after the US government began a separate leasing process covering 12.4 million hectares (31 million acres) of seafloor around American Samoa. Contracts are expected to be awarded in November.

American Samoa Governor Nikolau Pula said his government continued to oppose deep-sea mining, warning that untested extraction methods could damage the territory's tuna industry, a major driver of its economy.

On 19 August, environmental groups in American Samoa and Hawaii filed legal proceedings against the US government seeking to stop the proposed auction of seafloor permits around the islands. They alleged that federal agencies had failed to assess the potentially destructive effects of mineral extraction on marine ecosystems.

In a Hawaii court, Fa’asao Ameika Samoa and the Conservation Council for Hawaii argued that extraction machinery “can destroy nearly all life in its path” and “stirs up sediments that can introduce toxic substances into the food web and smother seafloor ecosystems”.

“Even just exploring for seabed minerals introduces extremely loud noise into the marine environment that can harm marine mammals and other wildlife,” the complaint reads.