The Trump administration is planning to build a 5,000-person military base in Gaza, sprawling more than 350 acres, according to Board of Peace contracting records reviewed by the Guardian.

The site is envisioned as a military operating base for a future International Stabilization Force (ISF), planned as a multinational military force composed of pledged troops. The ISF is part of the newly created Board of Peace which is meant to govern Gaza. The Board of Peace is chaired by Donald Trump and led in part by his son-in-law Jared Kushner.

The plans reviewed by the Guardian call for the phased construction of a military outpost that will eventually have a footprint of 1,400 metres by 1,100 metres, ringed by 26 trailer-mounted armored watch towers, a small arms range, bunkers, and a warehouse for military equipment for operations. The entire base will be encircled with barbed wire.

The fortification is planned for an arid stretch of flatlands in southern Gaza strewn with saltbush and white broom shrubs, and littered with twisted metal from years of Israeli bombardment. The Guardian has reviewed video of the area. A source close to the planning tells the Guardian that a small group of bidders – international construction companies with experience in war zones – have already been shown the area in a site visit.

The Indonesian government has reportedly offered to send up to 8,000 troops. Indonesia’s president was one of four south-east Asian leaders scheduled to attend an inaugural meeting of the Board of Peace in Washington DC on Thursday.

The UN security council authorized the Board of Peace to establish a temporary International Stabilization Force in Gaza. The ISF, according to the UN, will be tasked with securing Gaza’s border and maintaining peace within the area. It’s also supposed to protect civilians, and train and support “vetted Palestinian police forces”.

It is unclear what the ISF’s rules of engagement would be if there is combat, renewed bombing by Israel, or attacks by Hamas. Nor is it clear what role the ISF is meant to play in disarming Hamas, an Israeli condition to proceed with Gaza’s reconstruction.

While more than 20 countries have signed up as members of the Board of Peace, much of the world has stayed away. Although it was set up with the UN’s approval, the organization’s charter appears to grant Trump permanent leadership and control.

“The Board of Peace is a kind of legal fiction, nominally with its own international legal personality separate from both the UN and the United States, but in reality it’s just an empty shell for the United States to use as it sees fit,” said Adil Haque, a professor of law at Rutgers University.

Experts say the funding and governance structures are murky, and several contractors have told the Guardian that conversations with US officials are often conducted on Signal rather than over government email.

The military base contracting document was issued by the Board of Peace, according to a person familiar with the process, and prepared with the help of US contracting officials.

The plans say there is to be a network of bunkers each 6 metres by 4 metres and 2.5 metres tall, with elaborate ventilation systems where soldiers can go for protection.

“The Contractor,” says the document, “shall conduct a geophysical survey of the site to identify any subterranean voids, tunnels, or large cavities per phase.” This provision is likely referencing the large network of tunnels Hamas has built in Gaza.

One section of the document describes a “Human Remains Protocol”. “If suspected human remains or cultural artifacts are discovered, all work in the immediate area must cease immediately, the area must be secured, and the Contracting Officer must be notified immediately for direction,” it says. The bodies of about 10,000 Palestinians are believed to be buried under the rubble in Gaza, according to Gaza’s civil defense agency.

It is unclear who owns the land where the military compound is set to be built, but much of the south Gaza area is currently under Israeli control. The UN estimates that at least 1.9 million Palestinians have been displaced during the war.

Diana Buttu, a Palestinian-Canadian lawyer and former peace negotiator, called building a military base on Palestinian land without the government’s approval an act of occupation. “Whose permission did they get to build that military base?”

Officials from US Central Command referred all questions about the military base to the Board of Peace.

A Trump administration official declined to discuss the military base contract: “As the President has said, no US boots will be on the ground. We’re not going to discuss leaked documents.”