U.S. Secretary of State Marco Rubio visited Reliance Industries' Jamnagar refinery in Gujarat on Wednesday to discuss closer energy cooperation between Washington and the Indian conglomerate controlled by billionaire Mukesh Ambani.

Rubio said the U.S. wants to "work together more closely" with Reliance on refining energy from the Western Hemisphere, particularly Venezuelan crude. He told India's Network 18 that the arrangement benefits both India and the U.S. Reliance's Jamnagar facility processes 1.4 million barrels of crude per day, making it the world's largest single-site refinery.

Reliance has emerged as the biggest buyer of Venezuelan crude outside the U.S. as of September. Rubio indicated the company could expand Venezuelan purchases, noting that Reliance's refining capacity could help India diversify its energy supplies. He pointed out that Venezuela is ramping up energy production and that India has a history of refining Venezuelan crude. President Donald Trump has been pushing India to buy more Venezuelan oil to replace Russian barrels. While state-owned Indian oil companies have made opportunistic purchases, Reliance has been the primary buyer.

The visit underscores a deepening commercial relationship. Trump announced in March that America would build its first new oil refinery in 50 years with help from Reliance investment. Trump posted on Truth Social that the deal was worth $300 billion, calling it "the biggest in U.S. history." Reliance has not publicly confirmed the investment size. Pramit Pal Chaudhuri, South Asia practice head at Eurasia Group, told CNBC that Reliance's silence on the deal creates uncertainty. He said Rubio's visit aimed to either "clinch" the deal or advance it further.

Rubio told Network 18 that Reliance had invested in increasing U.S. refining capacity. He also referred to India as a "refining superpower" at a Tuesday press conference when asked about New Delhi's role in meeting global energy demand.

Chaudhuri noted that Indian and Chinese refineries excel at processing heavy and medium-heavy crude from Venezuela and Russia, grades better suited for producing diesel. U.S. diesel prices have surged recently, affecting truckers, farmers and shippers, with prices expected to remain elevated into next year.