Ukraine is to resume pumping Russian oil to Hungary in order to unblock a €90bn (£78bn) loan from the European Union.
Volodymyr Zelensky, Ukraine’s president, has agreed to the move after approving repairs to the Druzhba pipeline, which runs through his country to central Europe.
The pipeline, which has been offline since January after some of its infrastructure in western ​Ukraine was damaged in a Russian strike, supplies both Hungary and Slovakia.
Ukraine has also previously struck other sections of the pipeline in separate attacks.
However, Budapest and Bratislava had refused to sign off on a €90bn EU loan to Ukraine until it restored the flow of oil.
1202 Druzhba pipeline
Mr Zelensky has agreed, and hopes his olive branch will enable Viktor Orban, the prime minister of Hungary, and Robert Fico, the prime minister of Slovakia, to give their blessing to the loan when EU leaders meet in Brussels on Thursday.
A senior EU diplomat said leaders would use the summit to demand that Mr Orban drop his veto, honouring a deal he agreed to last year.
“Orban should deliver on his promise he made in December,” the diplomat told The Telegraph.
The source added: “But Hungary is currently still blocking the legislative proposal. We think that should stop, and that the money should flow as quickly as possible, because Ukraine needs it to stay in the fight.”
Mr Orban, who is fighting for re-election in a parliamentary vote next month, has repeatedly accused Kyiv of refusing to repair the pipeline for political reasons.
Neither the Hungarian prime minister nor Mr Zelensky has tried to hide his disdain for his counterpart in recent weeks, after the dispersal of the first loan payments was held up by the row.
Viktor Orban has repeatedly criticised Ukraine’s handling of the situation – Marton Monus/REUTERS
In an attempt to defuse tensions, EU officials have been urging the Ukrainian president to accept their help in restoring oil flows.
A Hungarian delegation was dispatched to inspect the damaged pipeline, but was blocked from visiting by Kyiv.
However, on the eve of the summit, it appeared that Mr Zelensky had finally relented to the offers of assistance.
“Allegations that Ukraine is deliberately obstructing oil transportation through the Druzhba pipeline are unfounded. The disruption results from recent Russian terrorist attacks on the pipeline and surrounding infrastructure,” he wrote in a letter to EU chiefs.
He added: “We are undertaking all possible efforts to repair the damage and restore operations, considering the impact on the pipeline itself, the surrounding infrastructure and environment as well.”
In response, Ursula von der Leyen, the president of the European Commission, and Antonio Costa, the president of the European Council, said: “The EU has offered Ukraine technical support and funding.
“The Ukrainians have welcomed and accepted this offer. European experts are available immediately.”
Ukraine and the EU are the main rhetorical targets of Mr Orban’s re-election bid and Peter Szijjártó, Hungary’s foreign minister, described the letter as “political theatre” co-ordinated between Kyiv and Brussels.
“The oil blockade against Hungary must be lifted immediately,” Mr Szijjártó said.