On Tuesday, Ukraine and Hungary summoned their respective ambassadors in a developing spat over Budapest’s signing of a new long-term gas contract with Russia, which Kyiv sees as a danger to its national security.

The flows will primarily pass through Russia’s newly constructed undersea gas pipeline TurkStream, rather than through Ukraine, which has expressed concern about politically motivated decreases in Russian transshipments for which it is compensated.

Ukraine’s Energy Minister was scheduled to meet with his European Union colleague over the matter, while Russia cautioned Ukraine not to meddle in the agreement, which coincides with larger European concerns about Russian gas supply policy amid rising gas prices.

On Monday, Hungary accused Ukraine of interfering in its domestic affairs after Kyiv chastised Budapest for signing a new 15-year natural gas supply agreement with Russia’s Gazprom.

Ukraine’s ambassador was summoned on Tuesday, according to Foreign Minister Peter Szijjarto, for what he described as Ukraine’s attempts to sabotage the gas supply contract.

“We see Ukraine’s desire to block a secure gas supply for Hungary as a violation of our sovereignty,” Szijjarto said in a statement.

On Monday, Ukraine claimed the agreement was a “purely political, economically unjustified choice” and that it would urge the European Commission to examine whether it complied with European energy law.

On Tuesday, Szijjarto claimed he was “outraged,” while Dmitry Peskov, a spokesperson for the Kremlin, downplayed Ukraine’s concerns and insisted the agreement was exclusively bilateral.

“No one’s rights are being violated, no norms are being violated,” he said in a daily press conference call, adding that no country has the authority to intervene.

TIT-FOR-TAT

Ukraine’s foreign ministry told Reuters on Tuesday it had summoned the Hungarian ambassador in a tit-for-tat move.

“Gas transportation bypassing Ukraine undermines our country’s national security and Europe’s energy security,” the foreign ministry’s spokesman said in a text message.

“The Ukrainian side will take decisive measures to protect national interests,” it said, without elaborating.

The EU’s executive commission said members were free to enter into bilateral gas agreements but should inform it within three months if they exceed 28% of annual consumption, noting the deal signed by Hungary, an EU member, exceeded that amount.

“Kadri Simson, the Commissioner for Energy, is meeting Ukraine’s Energy Minister German Galushchenko today,” a commission spokesperson said in an email. It did not elaborate on the meeting but said the commission could request to see a contract if there was a concern about security of supply.

Under the deal signed on Monday, which is effective from Oct. 1, Gazprom will ship 4.5 billion cubic metres of gas to Hungary annually, via two routes: 3.5 billion cubic metres via Serbia and 1 billion cubic metres via Austria. Russia’s total gas exports for 2021 are projected at 183 billion cubic meters.

The Russian gas giant has been accused by the International Energy Agency (IEA) and some lawmakers in the European Parliament of not doing enough to increase its natural gas supplies to Europe, where gas prices have risen sharply.

Russia has said it is meeting commitments and stands ready to boost supply.

Relations between Hungary and its neighbour Ukraine have been scarred for years by a dispute over the linguistic rights of some 150,000 ethnic Hungarians living in the western Ukrainian region of Transcarpathia.

Kyiv infuriated Budapest in 2017 with a law restricting the use of minority languages including Hungarian in schools.

Prime Minister Viktor Orban’s nationalist government responded by blocking former Soviet Ukraine’s efforts to build closer ties with NATO and the European Union.