1 of 2
MTI via AP, Szilard Koszticsak
Hungarian Prime Minister Viktor Orban addresses diplomats during the annual conference of heads of Hungarian missions abroad in the Ministry of Foreign Affairs and Trade in Budapest, Hungary, Monday, Feb. 29, 2016. Orban said neighboring Romania is waging a 'political campaign' against the leaders of Romania's large Hungarian minority.

BUDAPEST, Hungary — Romania is waging a 'political campaign' against the leaders of Romania's large Hungarian minority, Hungary's prime minister said Monday.

"Under the pretext of constitutionality, legality and the fight against corruption, in reality we have to register a political campaign against Hungarian politicians there," Prime Minister Viktor Orban told Hungarian diplomats, adding that Hungary would "have to raise this issue in the proper form."

Some 1.3 million ethnic Hungarians live in Romania, mostly on territory that Hungary lost after World War I, and the treatment of the minority has long been a contentious issue between the two countries.

Last week, Laszlo Tokes, an ethnic Romanian Calvinist minister whose protests sparked the fall of Romania's communist regime, was stripped by a court of a high state honor for suggesting in 2013 that Hungary should take on the "status of protector" for ethnic Hungarians in Romania's Transylvania region.

Tokes has had strained relations with Romanian officials mostly because of his advocacy for greater autonomy and rights for the Hungarian minority. He is a close ally of Orban.

The party representing the interests of Hungarians in Romania was in government between 2004 and December 2014, but decided to leave the coalition of former Prime Minister Victor Ponta after Ponta lost the presidential race to Klaus Iohannis, who was favored overwhelmingly by Hungarians.

Alison Mutler in Bucharest, Romania, contributed to this report.