Ukraine's SBU Security Service is investigating criminal proceedings on the receipt of Hungarian citizenship by citizens of Ukraine. Obtaining dual citizenship entails deprivation of Ukrainian citizenship, Ukraine's Prosecutor General Yuriy Lutsenko has said.

"The SBU is conducting an investigation, and we are in charge of procedural supervision. Obtaining dual citizenship is strictly forbidden under Ukraine's Constitution. There can be no two interpretations. If there is evidence of dual citizenship, it should be punished," Lutsenko told journalists in Kyiv on Thursday.

He said action will be taken if the SBU establishes "cases involving mayors, governors, ministers, pensioners or servicemen."

Ukrainian media earlier reported information about the issuance of Hungarian passports to Ukrainian citizens at the Hungarian consulate in Berehove in Zakarpattia region. A video clip was published showing persons taking an oath calling Hungary their homeland, as well as pledging to serve the country. Media said Hungarian diplomats urged those gathered not to inform Ukrainian state agencies that they obtained Hungarian citizenship.

Ukrainian Foreign Minister Pavlo Klimkin discussed the issue with his Hungarian counterpart Péter Szijjártó in the United States on the margins of the United Nations General Assembly meeting.

Klimkin said they discussed in detail what is happening at the Hungarian consulate in Berehove, but Szijjártó disagreed about violations committed by the Hungarian consul.