The rallies will take place in two of Texas’ energy centers as Republicans seek to build support in a competitive Senate race between Republican Attorney General Ken Paxton and Democratic state Rep. James Talarico.

The official said Rubio is accompanying Trump in his role as national security adviser and is not expected to address either rally. Rubio’s participation in the campaign swing is notable because he has largely focused on his State Department responsibilities rather than campaigning for the president.

The tanker visit is expected to highlight an agreement Trump secured in August involving Venezuelan oil. The agreement gives the United States majority control of more than 65 billion barrels of Venezuela’s oil reserves, according to the details reported at the time.

Trump has presented the deal, alongside other actions by his administration, as part of an effort to reduce gasoline prices. Voters have been frustrated by the effect of the Iran war on household costs, making fuel prices a prominent issue during the Texas trip.

The planned visit puts energy policy and the administration’s approach to Venezuela on display in a state central to U.S. oil production, while Trump makes an explicit appeal to supporters ahead of the Senate contest.