BUDAPEST (Reuters) - Hungary’s foreign minister on Wednesday said Budapest would block Ukraine’s membership in NATO until Kiev restored the rights that ethnic Hungarians had before a language law curbed minorities’ access to education in their mother tongues.

Hungary has clashed with Ukraine over what it says are curbs on the rights of roughly 150,000 ethnic Hungarians to use their native tongue, especially in education, after Ukraine passed a law in 2017 restricting the use of minority languages.

“We ask for no extra rights to Hungarians in Transcarpathia, only those rights they had before,” Szijjarto told state news agency MTI at the NATO summit in London.

Hungary has said it was open to consultations with Ukraine over the issue.

Relations between Ukraine and Russia collapsed following Moscow’s annexation of the Crimea peninsula in 2014 and its support for separatist rebels in eastern Ukraine in a conflict that has killed more than 13,000 people.

Language is a sensitive issue in Ukraine, where some Ukrainian speakers argue that the prominence of Russia is a legacy of the Soviet era that undermines Ukraine’s identity.

There has been a push in recent years to promote the Ukrainian language in state institutions, schools, television and the media.

The Venice Commission, an EU rights body, urged Ukraine in 2017 to ensure a substantial level of teaching in official languages of the European Union, such as Hungarian and Romanian, both of which have significant minorities in Ukraine.

It also said Ukraine should ensure a sufficient proportion of education in minority languages in addition to Ukrainian, allow more time for gradual reform, exempt private schools and enter into a new dialogue with minorities.

“Ukraine is complying with all the recommendations of the Venice Commission on the education law,” Ukrainian President Volodimir Zelenskiy said at a NATO press conference in October.