HOUSTON - The Trump administration on Monday signaled it is nearing approval for permits to mine the deep sea, part of a broader push to boost US access to the critical minerals used across much of the country's economy.

Interior Secretary Doug Burgum said during a gathering of G20 energy ministers in Houston that permits could come within months as the administration pursues a strategy of "energy addition" to expand supply chains for the country and allies.

Since returning to office last year, President Donald Trump has taken steps to bolster the nascent deep-sea mining industry, although he has yet to issue operational permits for it to proceed.

The specter of seabed mining being allowed to commence has alarmed many environmentalists owing to concerns that it could cause irreversible biodiversity loss.

Parts of the Pacific Ocean and elsewhere are estimated to contain large amounts of potato-shaped rocks known as polymetallic nodules that contain the building blocks for electric vehicles, weapons and electronics.

"Those nodules that we just have to go out and vacuum up off the (sea) floor are filled with these critical minerals that we need," Burgum said. "And of course, part of that is assuring that we've got diverse, secure, affordable supply of critical minerals."

US access to critical minerals — especially those processed by Chinese companies — has dwindled in the past 18 months as Beijing has limited exports. That, in turn, has ratcheted up pressure on Washington to support efforts to boost domestic mining.

When asked when the federal government could issue deep-sea permits, Burgum said: "Those discussions are going on right now," adding that, "You'll be hearing more in the weeks and months ahead because there's some exciting developments that are coming on that front."

Burgum's Interior Department oversees the Marine Minerals Administration, which must approve any permits to mine US territorial waters.

The MMA review process would start with a lease sale to give private companies exclusive access to mine part of the seabed. That would be followed by a process to consider an operational permit, which would take into account a range of scientific data.

Separately, Trump aims to have the Commerce Department issue international permits, a step that could set up a clash with the United Nations-backed International Seabed Authority, which has been trying to set standards for more than 25 years.

Companies that have formally asked for seabed mining permits include The Metals Company and privately held Impossible Metals. Several others have applied for exploration permits.