House Democrats are demanding a reckoning from the U.S. ambassador to Brazil after news reports there said he was urging country officials to lower ethanol tariffs to help President Trump’s chances of reelection.

In a letter Friday to Ambassador Todd C. Chapman, House Foreign Affairs Committee Chairman Rep. Eliot L. Engel (D-N.Y.) and Western Hemisphere subcommittee Chairman Albio Sires (D-N.J.) cited a report in prominent Brazilian newspaper O Globo depicting Chapman telling Brazilian officials about “the importance for the [President Jair] Bolsonaro government of maintaining Donald Trump as U.S. President.” In the article, according to the letter, Chapman also communicated to Brazilian officials that it was important for their “government to do the U.S. a favor” by reducing ethanol tariffs, as those are important in the state of Iowa, a potential “key player” in 2020.

Panel Democrats are asking Chapman to state in writing whether the comments are true, and back up his claim with documents related to his conversations with Brazilian officials, “to reassure Congress” that he “is truly representing the interests of the United States and not the narrow, political interests of President Trump.”

A spokesperson for the State Department’s Bureau of Western Hemisphere Affairs said in a statement that “allegations suggesting that Ambassador Chapman has asked Brazilians to support a specific U.S. candidate are false. The United States has long been focused on reducing tariff barriers and will continue do so.”

Chapman’s reported comments are reminiscent of Trump’s exhortation to Ukrainian President Volodymyr Zelensky to “do us a favor” during a July 25, 2019, call, the record and circumstances of which became the focus of the House Democrats’ case for impeaching Trump earlier this year. The reports regarding his comments about ethanol are also only the latest recent example of Chapman, a career diplomat, opining about matters that House Democrats believe come troublingly close to engaging in partisan politics.

Engel and Sires wrote in their letter that earlier this week, Chapman defended Eduardo Bolsonaro, a member of Brazil’s National Congress and the son of Brazil’s president, when he tweeted out a video supporting Trump’s reelection, saying he had a right to speak freely.

“It is simply not appropriate for sitting foreign government officials — in any branch of government — to promote the campaigns of candidates in the United States,” Engel and Sires wrote in their letter. “After everything that occurred in the U.S. presidential election in 2016, we frankly believe that you should know better.”

The committee asked for a response from Chapman by Aug. 4.