In his speech Thursday, Mr. Soros denied he was trying to interfere in Hungarian politics, and chastised Mr. Orban for trying to cast him as an enemy.

“He sought to frame his policies as a personal conflict between the two of us and has made me the target of his unrelenting propaganda campaign,” Mr. Soros said of the Hungarian prime minister. “He cast himself in the role of the defender of Hungarian sovereignty and me as a shady currency speculator who uses his money to flood Europe — particularly his native Hungary — with illegal immigrants as part of some vague but nefarious plot.”

Mr. Soros added, “This is the opposite of who I am.”

Opponents of the law have said it threatens not just C.E.U. but academic freedom in Hungary. Tens of thousands of people took to the streets of Budapest in April to protest the law. The European Commission took legal action and the European Parliament voted to begin a procedure that would penalize the Hungarian government for violating the bloc’s fundamental values.

The situation had been at a standstill for months until last week, when Andrew M. Cuomo, the governor of New York, where the university is registered, said in a statement that the state was open to negotiations. Hungary has said the same, and the government sent responses to the European Commission’s legal concerns in the case.

Mr. Orban, once a recipient of a Soros-funded scholarship, has repeatedly criticized Mr. Soros for his pro-democracy efforts in Hungary and elsewhere in Central and Eastern Europe. Populist leaders across the continent, echoing President Trump’s criticism of Mr. Soros, who supported Hillary Clinton in the 2016 presidential race, have accused Mr. Soros of trying to manipulate politics in their countries.