President Donald Trump has scheduled a campaign rally on Oct. 9 in Council Bluffs where he is expected to announce year-round access to gasoline with 15 percent ethanol, called E15.

The president's campaign website said the event will be held at 6:30 p.m. at the Mid-America Center with the doors opening at 3:30 p.m. There were no details about what Trump plans to say, but he hinted Monday about a possible upcoming trip to Iowa to announce "something very important" as he touted a new U.S. trade deal with Canada and Mexico.

Liz Bowman, an aide to U.S. Sen. Joni Ernst, R-Iowa, said in an email Tuesday night that any details about the president's trip would have to be addressed by the White House. "But we are optimistic that the visit is in regard to year-round E15," she said.

White House spokeswoman Vanessa Morrone said Tuesday night she couldn't confirm anything.

The Trump administration has previously said it will approve year-round use of E15, but the promise has yet to materialize. The increased use of ethanol is seen as a help to Iowa corn farmers, particular amid a slump in crop prices that haven't been helped by the Trump administration's trade battle with China.

E15 is banned in the summer, based on concerns it contributes to smog, a claim ethanol advocates say is unfounded. Almost all gasoline contains 10 percent ethanol.

Politico reported last week that Trump could visit Council Bluffs on Oct. 9 to campaign for Gov. Kim Reynolds and Rep. David Young, both Republicans, ahead of the November midterm elections.