President Trump visited Iowa today, where he met with numerous farmers, Gov. Kim Reynolds and Iowa Agriculture Secretary Mike Naig, who shared information about last week's derecho.

Trump promised to help rebuild Iowa during the visit, KCCI reported.

Watch Trump's disaster recovery briefing in Iowa.

On Monday, Trump approved part of Iowa's disaster aid request. The approval didn't include assistance for private property owners, USA Today reported. Reynolds requested $4 billion in disaster relief funding, The Hill reported.

Prior to the visit, the Iowa Renewable Fuels Association, Iowa Corn Growers Association, Iowa Soybean Association and Iowa Biodiesel Board sent a letter to the president, thanking him for the derecho disaster assistance, but beseeching him to take steps to create growing markets through a robustly implemented Renewable Fuels Standard.

"The loss of key export markets, abuse of Renewable Fuels Standard refinery exemptions by the EPA, and the economic downturn resulting from COVID-19 have combined to stretch rural Iowa to its limit," the letter reads.

The groups say the EPA has undermined the RFS by granting RFS refinery exemptions, destroying demand for more than 4 billion gallons of biofuels. Now, the EPA is considering retroactive "hardship" exemptions dating as far back as 2011.

Related:Derecho leaves path of damage in wake

"Make no mistake, we often hear from farmers: 'If we can't trust the Trump administration to do the right thing before the election, then why on earth would we expect them to treat us fairly after the election?' Many rural voters are waiting to see if you will uphold the RFS and your promise before the election," the letter reads.

Iowa Sen. Joni Ernst, a Republican, made it clear that Iowa farmers are waiting to see gap-year RFS exemption requests denied by EPA.

“We're pleased the president has committed to talking with EPA," said IRFA Executive Director Monte Shaw. "Now rural Iowans wait to see if Trump orders EPA to deny the baseless and illegal RFS waivers or be stonewalled by his own administration. Iowa is watching."

Trump stopped in Cedar Rapids on his way to Arizona to deliver remarks on immigration.

Click the download button below to download the letter to President Trump.