MEXICO CITY (AP) — Greenpeace activists have boarded a deep-sea mining ship in the Pacific Ocean between Hawaii and Mexico and said Sunday they’ll stay to protest exploration the ship is conducting to support activity that would destroy marine life.

Australian-owned The Metals Company, whose subsidiary runs the ship, accused the protesters of endangering the crew and breaking international law.

The escalating conflict comes as international demand for critical minerals found on the seafloor grows, but an increasing number of countries say more research is needed into the environmental impacts of deep-sea mining.

Greenpeace began the protest Thursday by positioning kayaks beneath the ship, Coco, for up to 10 hours at a time to block it from deploying equipment to the water.

In response, the company’s CEO Gerard Barron threatened an injunction on Saturday afternoon — according to correspondence shared by Greenpeace and reviewed by The Associated Press — alleging protesters broke international law and jeopardized the safety of crew members.

During the protest one kayak was capsized by propeller wash when Coco accelerated without warning, Greenpeace claims. Legal representatives from The Metal Company’s subsidiary NORI said this was an example of how the protest was not safe.

No injunction has been filed yet, according to Greenpeace. The company said it would use all legal measures available to protect stakeholders’ rights.

Later that day, two activists boarded Coco. They will remain camped on the main crane used to deploy and retrieve equipment from the water until The Metals Company agrees to leave, according to Louisa Casson, head of Greenpeace’s campaign against deep-sea mining.

“We will continue to try and disrupt as much as we can, because we are very concerned that this is a tick-box exercise that is purely designed to gather data so they can put in a mining application next year,” Casson said Sunday, from a Greenpeace ship near Coco.

A subsidiary of The Metals Company has been conducting exploratory research in the Clarion Clipperton Zone since 2011. They say data from their latest expedition, researching how the seabed recovered from exploration last year, will be used in an application to begin mining in 2024.

Greenpeace’s “actions to stop the science suggest a fear that emerging scientific findings might challenge their misleading narrative about the environmental impacts,” Barron told The Associated Press in response to the camping protesters.

He added that if research were to show their mining would be unjustifiably destructive The Metals Company is “100%” prepared to withdraw.

Casson said the company’s actions suggest that is not true. “That they are doing this in the interest of science is really very questionable,” said Casson. “There is a clear economic motive: they are entirely a deep-sea mining company.”

As they suck up nodes from the sea floor, The Metals Company said they expect mostly to find manganese, which President Joe Biden declared a critical mineral last year. Driven by clean energy technologies, demand for other key battery ingredients like lithium has as much as tripled, according to a market review this July.

“It makes sense to be able to extract these raw materials from parts of the planet where there is the least life, not the most life,” said Barron. “You can’t get away from the fact there’s about 10 grams of biomass per square meter in the abyssal plains,” much less than at most terrestrial mines.

That, said Casson, is an apples and oranges comparison, when studies also show over 5,000 species inhabit this part of the Pacific, which scientists say would be harmed by light and sound pollution, as well as huge clouds of dust.

On Tuesday this week Mexico joined a coalition of 23 other countries calling for a moratorium on deep-sea mining. While France alone sought an outright ban, the other signatories are requesting a pause for more research into the effects of deep-sea mining.