The Justice Department has notified Las Vegas casino mogul Steve Wynn that he must register as a foreign agent acting on behalf of China or face a court battle, The Wall Street Journal reports. In 2017, Wynn spoke with a Chinese government official about a Chinese billionaire, Guo Wengui, and later lobbied Donald Trump’s administration to deport the businessman from the U.S. back to China, where he’s a wanted fugitive. Guo is charged with sexual assault, bribery, and other crimes; he has denied accusations of wrongdoing and called them political persecution. He has also been linked to former Trump adviser Steve Bannon. The DOJ has told Wynn—who once had business ties to gambling hotspot Macau—that he must register under the Foreign Agents Registration Act or face litigation forcing him to comply. Wynn’s attorney told the Journal, “Steve Wynn never served as an agent or lobbyist for China or anyone else.” Guo welcomed the news in a statement, calling Wynn “a greedy spy of the Chinese Communist Party.”