Donald Trump suggested Venezuela become the 51st state of the United States on Tuesday as the president showed off a tanker he claimed had “one million barrels of oil on it” from the country, nine months after deposing its president.

At a campaign rally in Corpus Christ, Texas, Trump touted a US oil deal with Venezuela, which the US attacked in January, capturing its long-serving leader Nicolás Maduro.

Trump claims the agreement – struck with the South American country’s interim government, which is backed by Trump’s administration – will cover “billions” of barrels of oil.

Venezuela “will become a prosperous country, and who knows? Maybe some day soon it’ll become a prosperous 51st state,” Trump said at the podium on Tuesday. “That’s possible.”

Venezuela is on a growing list of countries and territories Trump has spoken of acquiring, including Greenland, Canada and Mexico.

With tens of millions of Americans set to vote in next week’s midterm elections, Trump’s aggressive foreign policy – including his controversial war on Iran, and tariffs on goods from much of the world – have challenged his popularity, according to opinion polls, with his approval ratings falling to record lows.

But on Tuesday, the president sought to point to the Venezuela operation as an example of his success. US fuel prices, which surged after the start of the Iran war, piling pressure on Americans’ cost of living, “will soon come plummeting down”, he claimed in a social media post.

“We’re celebrating the greatest oil victory in history,” he said at the rally, pointing out the ship off the Texan coast. “The oil provided is being provided to the United States at zero cost to the American taxpayer.”

Moments before Trump took the stage in Texas, he claimed on his Truth Social platform: “By unleashing Energy Dominance from Alaska, all the way down to Venezuela, I have made the Western Hemisphere the Energy Capital of the World.”

The deal has also drawn skepticism as critics complained that the Trump administration has not pushed a transition to democracy in Venezuela, were elections have not been held since Maduro was detained by US forces and taken to New York to face criminal charges after a raid on his Caracas residence.

The urgency of the oil agreement stems from Trump’s opting into the war with Iran in February. Gas prices have shot up nationwide after Iran closed the strait of Hormuz, a passageway for 20% of the world’s oil supplies.