Ukrainian nationalists have torn down and tried to burn the flag of Hungary in a western Ukrainian town near the Hungarian border, in the most recent in a series of attacks by right-wing radicals on both sides of the border.

On Sunday, around 50 activists from the Svoboda nationalist group took part in a rally in the town of Beregovo (Berehove) in the Zakarpatye region. The nationalists removed the Hungarian flag from the town hall and tried to set it on fire, but were prevented from doing so by police.

The demonstrators, many of whom were veterans of Kiev’s so-called “anti-terrorist operation” in Eastern Ukraine, burned flares and chanted “Shame on you,” allegedly decrying the inability of the Ukrainian authorities to counter Hungarian influence in the region. The Beregovo area has a 76 percent majority Hungarian population, according to the 2001 census.

Zakarpatye Governor Gennady Moskal said that he was “outraged by the behavior of the right-wingers.” The governor stressed that the radicals had no support in Zakarpatye, saying that those behind the protest were “a bunch of marginals,” brought in from other Ukraine’s regions, Lvov, in particular.

Hungary summoned the Ukrainian ambassador in Budapest, Liuba Nepop, after the attack on the flag. Hungarian Foreign Minister Peter Szijjarto urged Kiev to investigate the incident, saying that perpetrators should be “detained and prosecuted as soon as possible.”“Such events can’t be tolerated in a well-functioning and European-aspired country,” Szijjarto told Hungarian media at a press conference.

On Saturday, local radical group Karpatskaya Sech staged a rally under the slogan, “No to Hungarian supremacism,” in Uzhgorod in western Zakarpatye. During the protest, the nationalists blocked the entrance to the local Hungarian Consulate.

In July, the leader of the Kiev-based C14 radical group, Evgeny Karas, visited Zakarpatye and wrote on Facebook that Hungarian influence had “paralyzed” Ukraine. According to Karas, the Hungarians “pour money on our lands. Recruit traitors. They’re building a foothold. Underground militarized units of Hungarians are already active on our territory. They train with the Hungarian army twice a year. The SBU (Ukrainian Security Service) is powerless… Only the nationalists and participants of the anti-terror operation care. But we won’t give away our lands.”

Hungarian nationalists on the other side of the border are demanding that Zakarpatye is returned to Hungary, as the land only became part of Ukraine in 1945, having been Austria-Hungarian for a long period before then.

A rally calling for “self-determination” for Zakarpatye was staged by the Hungarian nationalist Jobbik party in Budapest in mid-October. According to the Ukrainian ambassador, around a hundred demonstrators demanded freedom for national minorities in Ukraine and decried the Ukrainian authorities, whom they accused of “taking Ukraine hostage and their Hungarian brothers with it.”

The rally in the Hungarian capital went on, despite Kiev demanding that Budapest ban it. “What is it? Hungary is supporting separatism,” Ukrainian Foreign Minister Pavlo Klimkin wrote on Twitter in the wake of the protests.

Relations between the two neighbors are also complicated by a controversial education law adopted in Ukraine in September. The legislation states that all classes in secondary schools can be taught in no other language but Ukrainian.

READ MORE: No place for Ukraine in EU, Hungary says after Kiev outlaws education in minority languages

Hungarian FM Szijjarto has blasted the law as a “stab in the back,” labeling it a serious step backward in safeguarding “minority rights” in Ukraine. In retaliation, Budapest promised to “block all steps within the European Union that would represent a step forward in Ukraine’s European integration process” and recently vetoed the NATO-Ukraine summit, which was scheduled for December.