Former national security adviser Michael Flynn received substantial paychecks from Russian entities in the year before joining Donald Trump’s campaign as a surrogate, newly released documents reveal. The payments include previously reported disbursements from the Kremlin-backed RT network, as well as from two separate Russian companies, and are likely to renew questions about the Trump campaign’s friendliness toward Russia.

Flynn attended a 10th anniversary gala for RT in December 2015, for which the government-funded network paid him $45,386, according to documents published Thursday by Rep. Elijah Cummings (D-Md.), ranking member of the House Oversight Committee. Flynn, who had then most recently served in government as the director of the Defense Intelligence Agency, sat a few seats away from Russian President Vladimir Putin at the event. Flynn’s final cut was $33,750, after his speakers’ bureau, Leading Authorities, took a 25 percent commission.

The documents also show that in July 2015, Flynn received two separate payments of $11,250 from Volga-Dnieper, a cargo airline, and Kaspersky Government Security Solutions, a cybersecurity firm. Both companies are privately owned and based in Russia, though Flynn appears to have given talks to branches based in the U.S., according to Yahoo News.

Read the documents:

House Democrats quickly seized on the documents as evidence that Flynn may have violated the Emoluments Clause of the U.S. Constitution, which prohibits top government officials from accepting payments from foreign governments.

“I cannot recall any time in our nation’s history when the President selected as his National Security Advisor someone who violated the Constitution by accepting tens of thousands of dollars from an agent of a global adversary that attacked our democracy,” Cummings wrote in a statement. “I also cannot recall a time when the President and his top advisers seemed so disinterested in the truth about that individual’s work on behalf of foreign nations ― whether due to willful ignorance or knowing indifference.”

Cummings also sent a letter to Trump, Defense Secretary James Mattis and FBI Director James Comey asking for clarity on whether Flynn had disclosed during his vetting process his communications with foreign agents and financial involvement with other foreign sources. Cummings has also requested that the Defense Department take steps to recover all foreign funds accepted by Flynn that may have been in violation of the Emoluments Clause.

Flynn resigned as Trump’s national security adviser in February, amid controversy over his characterization of discussions he had with Russian ambassador Sergey Kislyak in December. Although Flynn ultimately admitted to discussing U.S. sanctions against Russia with the ambassador, he’d previously told Vice President Mike Pence that the topic hadn’t come up.

Last week, Flynn filed lobbying disclosure forms revealing that he was paid more than $500,000 last year to lobby on behalf of the Turkish government in its effort to discredit the exiled cleric Fethullah Gülen.

The White House has claimed Trump was unaware of Flynn’s work on behalf of a foreign government when he selected Flynn to serve as national security adviser.