Ukrainian Foreign Minister Pavlo Klimkin has suggested that Russia was behind recent attacks on a Hungarian cultural center in the western city of Uzhhorod.
"Russian ears are sticking out everywhere," Klimkin wrote on Twitter on March 5, in a reference to incidents on February 4 and February 27 in which Molotov cocktails were thrown into the building.
Klimkin thanked police for apprehending suspects and expressed concern that what he called "attempts to destabilize" the situation in Ukraine.
The chief of Ukraine's National Police, Serhiy Knyazev, wrote on Facebook on March 4 that three suspects in the February 27 incident -- which caused a fire that destroyed much of the first floor of the center -- were detained in Ukraine.
Without naming a country, he said that a foreigner suspected of being behind the attack remained at large.
Knyazev also said that two men suspected in the February 4 attack had been arrested in neighboring Poland.
Ukrainian police said earlier that the two Polish suspects arrested in Warsaw belonged to a radical group and that some of that group's members have fought alongside Russia-backed separatists in eastern Ukraine.
The attacks led to tension between Ukraine and Hungary, which has accused Kyiv of failing to protect ethnic Hungarians.
More than 100,000 ethnic Hungarians live in Zakarpattya, Ukraine's westernmost region, mostly in towns and villages close to the Hungarian border.