Russia agreed to resume gas supplies to Ukraine over the winter under a deal clinched late Friday with the European Union, capping months of difficult talks overshadowed by the Ukrainian conflict.

European Commission vice president for energy, Maros Sefcovic, told a news conference the preliminary deal was a “crucial step” to ensure Ukraine has gas supplies from October through March and that Europe receives onward deliveries.

“We just initialed a trilateral agreement for the upcoming winter,” Sefcovic said after nearly six hours of talks with the Russian and Ukrainian energy ministers in Brussels.

He added that “all technical details” were agreed on and the framework was set, but confirmation and formal signing of the full agreement would require separate procedures.

“I’m confident that the agreement will soon be confirmed and smoothly implemented,” he said after tweeting earlier it was a “major achievement.”

Ukrainian Energy Minister Volodymyr Demchyshyn told reporters “commercial conditions were acceptable” and that he expected the deal to be signed shortly.

“I’m sure we will be preparing for the heating season and start pumping gas into storage shortly,” he said.

“Ukraine confirmed in this document its capacity to ensure uninterrupted transit of Russian gas to EU partners,” he added.

Russian Energy Minister Alexander Novak said, “We will spare no effort to avoid any issues, problems.”

Novak said Moscow’s offer included a cut of “about $20″ per thousand cubic meters from the provisionally set price of $252.

He said the price agreed upon was competitive with those for gas supplied to countries neighboring Ukraine.

Sefcovic said the European Commission, the executive arm of the 28-nation EU, would continue arranging for EU and international financing of Ukraine’s winter gas purchases.

“At least $500 million should be available by the end of this year,” he said.