President Donald Trump said Sunday that Russia and Ukraine had agreed to an immediate energy cease-fire, but Ukrainian President Volodymyr Zelensky said the announcement was news to him.

In a Truth Social post, Trump said both sides had agreed. Zelensky said Ukraine was ready to accept an energy cease-fire if Russia agreed, and asked when it would start if Trump had negotiated it with Russian President Vladimir Putin. Trump gave no details about how long the purported agreement would last.

Ukraine has struck Russian energy facilities, particularly refineries, in retaliation for similar Russian attacks in Ukraine. The Trump administration has blamed Ukrainian strikes on Russian refineries for rising diesel prices. Trump’s announcement came days after he disclosed plans for the United States to buy diesel from Russia.