The United States imposed sanctions on a senior member of the Hungarian government for alleged corruption, the U.S. Treasury said on Tuesday, a move Budapest said it would challenge when President-elect Donald Trump takes power.

On Tuesday, a top Hungarian government official and adviser to Prime Minister Viktor Orban was sanctioned for alleged corrupt activity by the United States, according to the U.S. Department of State.

By Tamas Csonka The US has sanctioned Antal Rogan, a close ally of Hungarian Prime Minister Viktor Orban, for his alleged leading role in systemic public corruption in Hungary, outgoing US Ambassador David Pressman informed local media at an extraordinary press conference on January 7.

The US has placed Viktor Orbán’s chief of staff under sanctions for alleged corruption, the highest-ranking Hungarian official to be blacklisted since the fall of Communism. Antal Rogán, a longtime ally of the Hungarian prime minister overseeing state-owned media and part of the intelligence services,

Antal Rogan is the first high-ranking Hungarian official sanctioned by the U.S. under the Magnitsky Act, which targets individuals involved in serious human rights abuses and corruption.

The U.S. administration announced on Tuesday that it would sanction Antal Rogan, the head of Hungarian Prime Minister Viktor Orban's cabinet, for corruption. According to the State Department, the case of the prime minister's close associate exemplifies "state capture by oligarchs and undemocratic actors.