KYIV, Dec 1 – Tensions escalated sharply between Ukraine and Hungary after Budapest has summoned the Ukrainian ambassador in reaction to the Ukrainian security service SBU raiding the offices of an ethnic Hungarian group in ThransCarpathia.

The developments follow a spat between the two countries in October following allegations that Budapest may have tried to interfere in Ukrainian local election by trying to promote ethnic Hungarian politicians.

The escalation is a major setback as the two countries have been working to over the previous 12 months to improve relations that would open the door for Ukraine’s cooperation with NATO.

The Hungarian Cultural Association in Transcarpathia said in a statement that SBU officers had raided the association's headquarters and the home of its chairman, searching for evidence of "activities aimed at violently changing the borders," RFE/RL reported.

The association called on Ukrainian authorities to end what it called a "witch-hunt."

The SBU confirmed the raid and others in a statement on its website.

It said it conducted searches at local charitable foundations in the Transcarpathian region, checking "information about the involvement of the foreign fund in activities aimed at violating the state sovereignty of Ukraine."

Hungarian Foreign Minister Peter Szijjarto said on Monday that Hungary had protested the raids at Ukraine's Foreign Ministry and added he would raise the issue at a meeting of NATO foreign ministers beginning on December 1.

The two countries have repeatedly clashed over what Hungary says are curbs on the rights of around 150,000 ethnic Hungarians living in Ukraine to use their native tongue, especially in education. Ukraine passed a law in 2017 restricting the use of minority languages in schools.

Last month Ukraine barred entry to two Hungarian government officials over what Kyiv called meddling in local elections, an accusation Hungary denied.

Hungary has repeatedly hinted at blocking Ukraine's membership of NATO. (rfe/ez)