An American oil company connected to Donald Trump is preparing to sink wells in remote Greenland despite not having received permission from the local authorities.

As the US president renews his threats to claim the vast Arctic territory, materials to prepare for drilling were brought ashore in recent days on Greenland’s eastern coast.

That has prompted Greenland’s government to issue a “strong warning” that no approval had been granted to land the kit. “All future logistical matters must be advised and approved by the mineral resources authority – before they are carried out,” the government said in a statement.

Two days later, Trump made his latest menacing post on Truth Social, showing himself looming over a Greenlandic village.

Executives of Greenland Energy, a Texas company set up last year, have claimed that $1tn of crude may lie beneath the Jameson Land region. They announced plans to spend $60m drilling two wells to find out.

Although Greenland stopped issuing new oil licences in 2021 on environmental grounds, a UK company called 80 Mile had secured exploration rights in Jameson Land. Greenland Energy’s corporate filings say it will take a majority stake in the project in exchange for funding the exploration, though it still needs government permission to proceed.

Greenland Energy has retained Phil McGraw, better known as Dr Phil, a prominent rightwing former chatshow host who served on Trump’s religious freedom commission, to make a documentary series that will “capture the mission of these modern-day wildcatters”.

It has also appointed as a director a US navy veteran who is working on Golden Dome, the missile defence plan for which Trump says controlling Greenland is “vital”.

Larry Swets, Greenland Energy’s chair and a big shareholder, appears to enjoy access to Trump’s circle. He has said the oil project is “not related to American annexation”.

After a company representative falsely claimed at a Jameson Land community meeting in June that it had permission to land drilling equipment, Swets said: “Our enthusiasm for the project led us to communicate in a way that created confusion.”

But the next month, local people in the sparsely populated region noticed a tug pulling a barge shorewards and unloading a dozen containers. “The goal was to get the equipment onshore at Nunap Qeqqa [Jameson Land] in connection with planned oil exploration drilling,” the Greenland government’s statement said.

The Danish investigative outlet Danwatch quoted the head of the shipping company as confirming the delivery was for Greenland Energy.

Greenland Energy has declined to respond to questions from the Guardian. A letter it sent to shareholders on Thursday said: “Recent high-level meetings between project leadership and Greenlandic regulatory and oversight authorities have been constructive, and we continue to be encouraged by the progress being made toward the remaining approvals required for drilling.” It said that after those discussions, just one well would be drilled to begin with.

As a semi-autonomous territory of Denmark, decisions about Greenland’s natural resources rest with its local elected leaders, who now face a delicate decision. They could grant permission for oil drilling, even though the planned wells appear to fall within a conservation area protected by the Ramsar convention on wetlands. Or they could refuse and, some worry, give Trump a pretext to advance his imperialist agenda.

The Greenland government’s statement said it “would not be proportionate” to demand the equipment be removed. An application for permission remained under processing, it added.

A Greenland Energy representative has said a vessel carrying its 300 shipping containers of drilling equipment is to set sail from Canada on 12 September. Sinking the wells would begin in October.

Jeff Landry, the hard-right Louisiana governor serving as Trump’s Greenland envoy, has said Greenland could be pumping oil next year.