WASHINGTON (Associated Press)—President Donald Trump’s former national security adviser, Michael Flynn, who was fired from his prominent White House job last month, has registered as a foreign agent with the Justice Department for $530,000 worth of lobbying work that may have aided the Turkish government.

A lawyer for the former U.S. Army lieutenant general and intelligence chief said in paperwork filed Tuesday with the Justice Department’s Foreign Agent Registration Unit that Flynn was voluntarily registering for lobbying that “could be construed to have principally benefited the Republic of Turkey.”

Under the Foreign Agent Registration Act, U.S. citizens who lobby on behalf of foreign government or political entities must disclose their work to the Justice Department. Willfully failing to register is a felony, though the Justice Department rarely files criminal charges in such cases. They routinely work with lobbying firms to get back in compliance with the law by registering and disclosing their work.

Flynn’s attorney did not respond to questions about whether the Justice Department or FBI had contacted Flynn about his lobbying activities.

Flynn’s consulting firm, Flynn Intel Group Inc., had previously disclosed to Congress that it worked for Inovo BV, a Dutch-based company owned by a Turkish businessman. But neither Flynn nor his company had previously filed paperwork with the Justice Department, which requires more extensive transparency about work that benefits foreign governments and political interests.

In the filings with the Justice Department, Flynn’s attorney, Robert Kelner, noted they served as a termination of the registration, saying the firm had ceased operations in November, the same month the lobbying contract ended.

Under a Trump administration ethics pledge that post-dated his company’s work, Flynn agreed not to lobby for five years after leaving government service and never to represent foreign governments.

Calls to phone numbers associated with Flynn and his firm weren’t answered. Kelner, his attorney, declined to comment through a spokesman for his law firm, Covington & Burling.

Reached Wednesday afternoon, an official at the Turkish embassy in Washington said he would refer the questions to the embassy spokesman. The spokesman did not immediately respond.

The White House did not immediately respond to requests for comment Wednesday afternoon.

Trump fired Flynn last month for misleading Vice President Mike Pence and other administration officials about his contacts with Russia’s ambassador to the U.S., Sergey Kislyak.

As a key member of Trump’s transition team last December, Flynn spoke by phone several times with Kislyak during the period when former President Barack Obama expelled 35 Russian diplomats from the U.S. and levied new sanctions in response to Russian election-related hacking.

According to the new paperwork, Flynn’s firm took on the Turkish-related lobbying work last August while he was a top Trump campaign surrogate. Flynn’s consulting firm said its lobbying work ended in November, when the company ceased operations.

Flynn Intel disclosed in its filing that the company was invited by its Turkish client, Ekim Alptekin, to meet with Turkish officials in New York in mid-September. Among those officials, the documents said, were Turkey’s ministers of foreign affairs and energy. Flynn’s company did not name the officials but reported the two worked for Turkey’s government “to the best of Flynn Intel Group’s current understanding.”

In late October and early November, Flynn wrote an op-ed promoting Turkey’s political and business affairs that was later published in The Hill, a Washington-based political newspaper. In the new filing, Flynn disclosed that in writing the op-ed, he relied on research conducted as part of the Inovo BV contract.

But Flynn’s filing emphasized that neither Inovo BV nor the Turkish government directed him to write the article. He also said he was not paid for the op-ed.