Investor interest in the nascent sector has been intensifying, fueling optimism initially driven by research startups and junior exploration companies.
The Secretary of State's comments came after President Donald Trump questioned whether Russian President Vladimir Putin wants to "stop the war" against Ukraine.
The practice of deep-sea mining involves using heavy machinery to remove minerals and metals from the seabed, where they build up into potato-sized nodules.
The trust between Europe and the U.S. is not yet broken despite President Donald Trump's tariff policies, Joerg Kukies, acting German finance minister, said.