European Commission President Ursula von der Leyen says she made progress in talks with Hungarian Prime Minister Viktor Orban on a possible European Union-wide ban on Russian fossil fuels.
"This evening's discussion with PM Viktor Orban was helpful to clarify issues related to sanctions and energy security," von der Leyen said on Twitter. "We made progress, but further work is needed."
Von der Leyen said she would convene a teleconference with the leaders of other countries in the region to strengthen regional cooperation on oil infrastructure.
A sixth round of EU sanctions including a ban on Russia oil has been drawn up by experts in the European Commission, but Hungary and other member states, including Slovakia and the Czech Republic, have reservations.
European diplomats in Brussels are locked in negotiations on the sanctions, which are designed to punish Russia for its invasion of Ukraine, as they seek to achieve the backing of all 27 EU member states.
The package proposes most EU members halt oil imports from Russia by the end of the year.
Hungarian Foreign Minister Peter Szijjarto also said the two sides "made progress" in the talks in Budapest on May 9 but that they still had plenty to discuss.
"We cannot make the Hungarian people pay the costs of this war," he said on Facebook.
He said the Hungarian side informed von der Leyen "in detail" about the problems that the sanction package would cause, saying it would destroy Hungary's energy security.
"We asked that these issues be considered. Until the European Commission offers a solution to these problems, Hungary of course cannot support this sanctions package," Szijjarto said.
Before the talks over a working dinner at Orban's headquarters in Budapest's former Carmelite monastery, Orban's international spokesman, Zoltan Kovacs, signaled Hungary's position, saying on Twitter that the proposal was "like an atomic bomb for the Hungary economy and would destroy our stable energy supply."
Technical talks continue, and negotiators insist there is united EU support behind the need for tougher sanctions.