Hungary has stopped supplying gas to Ukraine through a “reverse flow” pipeline just days after the head of Russia’s Gazprom monopoly visited Budapest, Ukraine’s gas utility said.

Naftogaz, the Ukrainian distributor, said Hungary had stopped transporting gas at 19.00 Ukrainian time on Thursday, notifying Kiev that it was halting supply “for technical reasons” until further notice. It came after Alexei Miller, Gazprom chief executive, on Monday met Hungary’s premier Viktor Orbán, Naftogaz said.

The stoppage put further pressure on Ukraine and the EU ahead of trilateral talks with Russia in Berlin on Friday over restoring gas supplies to Ukraine after Gazprom suspended them because of a dispute over pricing and payment arrears.

Hungary, together with Slovakia and Poland, have been helping Kiev by re-exporting gas to Ukraine by reversing the flow in transit pipelines. Poland and Slovakia have reported reductions in their supplies from Russia in recent weeks, apparently aimed at limiting their ability to re-export to Ukraine.

Gazprom has said it is continuing to supply contracted amounts of gas to west European countries, but was not fulfilling demands for “extra” volumes as it needed to fill storage facilities before the onset of winter.

Hungarian officials could not immediately be reached for comment. But the country’s development ministry announced late on Thursday that it would increase gas imports from Friday to accelerate filling up its gas storage facilities ahead of winter, saying this was an “absolute priority”.

FGSZ, Hungary’s pipeline operator, said in a statement that gas system users had notified it of a “significant increase” in incoming gas deliveries. It said it had to interrupt supplies to Ukraine “to enable all pipelines to be suited for inward transmission”.

The Hungarian operator said it had been delivering up to 16.8m cu m of gas per day to Ukraine, equivalent to up to 6.1bn cu m per year, since March 2013. But it said capacity was not guaranteed and its ability to deliver depended on “prevailing technical and commercial conditions”.

Energy experts have warned that EU countries could face gas shortages this winter if Russia does not resume supplies to Ukraine, since volumes of gas in huge storage facilities in Ukraine are much lower than usual due to the summer cut-off.

Naftogaz said it had a supply contract with private companies in western Europe to supply gas to Ukraine via Hungary. But on Thursday afternoon FGSZ stopped providing transit facilities to these companies.

“Naftogaz deeply regrets this decision of FGSZ and calls on its Hungarian partners to respect their contractual obligations and EU legislation,” the Ukrainian distributor said. “Such a decision goes against the core principles of the EU single energy market”.

The EU’s gas commissioner, Günther Oettinger, who is taking part in the Berlin talks on Friday, called earlier this week for Russia and Ukraine to sign an interim gas agreement for the winter to prevent supply disruptions.

He said the agreement should include an interim price for a specified volume of gas, while the two countries continued to try to resolve their differences on pricing and arrears through arbitration.

By Neil Buckley, East Europe Editor