US President Donald Trump on Tuesday said Indian energy giant Reliance Industries was backing a deal to build the first new major oil refinery in the United States in half a century.

Trump made the announcement via his Truth Social platform, saying the company America First Refining would construct the new facility at the Port of Brownsville, Texas.

“This is a historic $300 billion dollar deal — the biggest in US history,” Trump wrote, framing the project as a cornerstone of his energy agenda, but offering no details on the plan.

“Thank you to our partners in India, and their largest privately held Energy Company, Reliance, for this tremendous Investment,” he said, without specifying the company’s commitment.

Reliance is India’s biggest privately held conglomerate and its Jamnagar refinery is the world’s largest.

The America First Refining website says the company is a project of Element Fuels, which first announced plans in 2024 to build a Brownsville refinery at a cost of between $3-$4bn.

The facility would be the first refinery built on the Gulf of Mexico since the 1970s, and the only one designed to process 100 per cent American shale oil, the company said.