BUDAPEST, Hungary (AP) — Changes by Hungary to its law on higher education which effectively forced a university founded by George Soros to leave the country were not in line with European Union law, according to an opinion issued Thursday by the bloc's highest court.

The opinion also said the EU's executive Commission should uphold its action against Hungary to ensure that the amendments approved by Hungarian legislators in 2017 comply with EU rules.

Among the changes, Hungary tied the operation of foreign universities in Hungary to a bilateral agreement between the Hungarian government and the universities' country of origin. Foreign universities were also compelled to carry out educational activities in their home countries.

At the heart of the conflict is the fate of Central European University, established in New York state by Soros, a Hungarian-American financier. It had to relocate most of its main activities to Vienna from Budapest, where it had been operating since the early 1990s.

Hungarian Prime Minister Viktor Orban has been a vocal critic of Soros for years, arguing that the billionaire philanthropist is intent on undermining European values with his liberal views on migration, claims Soros has denied. Orban's ideological aim of creating an “illiberal state” is also in contrast with Soros' ideal of an “open society.”

In light of his views on Soros, the amendments were widely seen as targeting CEU. The Court of Justice of the European Union said CEU was “the only foreign higher education institution then active in Hungary which did not meet the new requirements."

The EU Commission launched an infringement procedure in April 2017 against Hungary in the wake of the changes. It subsequently referred Hungary to the Court of Justice in December 2017.

The Hungarian government refused to sign an agreement with New York state regarding CEU and also rejected CEU's educational activities in New York, established through partner institution Bard College.

According to Thursday's nonbinding opinion by Advocate General Juliane Kokott, Hungary must “treat foreign and national higher education institutions equally” and the amendments in question are incompatible with the General Agreement on Trade in Services, or GATS, which is part of EU law, and with the EU's Charter of Fundamental Rights.

The EU's Court of Justice, based in Luxembourg, is beginning its deliberations over the case. While it is not forced to follow the opinion of the Advocate General, the court's rulings are often similar to the opinions.