Russia and Ukraine pounded each other with heavy overnight missile attacks as diplomatic efforts to end the war faltered, with the White House saying there were no imminent plans for presidents Donald Trump and Vladimir Putin to meet.

But Russian Foreign Minister Sergei Lavrov on Tuesday dismissed the idea of halting the conflict at the current contact line. Moscow was only interested in "long-term, sustainable peace", Lavrov said, implying that freezing the front line would only amount to a temporary ceasefire.

Ukraine's defense ministry said it continues to hit Russia's industries, "weakening the offensive potential of the aggressor state."

The European Union's 19th package of sanctions against Russia will list four companies involved in China's oil industry that circumvent Western restrictions, EU diplomatic sources said on Wednesday.

The Polish foreign minister said he could not guarantee that Russian President Vladimir Putin's plane would not be forced to land.

Trump wants Russia and Ukraine to freeze the war on the current battlelines, with Moscow holding a huge swathe of eastern Ukraine.

Russia is set to deliver around 750,000 barrels, or 100,000 metric tons, of a mix of Arctic heavy ARCO oil and gas condensate, a type of light oil, to Syria's Banias port, traders said and LSEG data showed.

U.S. president wants a swift end to the conflict, but both sides are digging in over the region in Ukraine’s east.

Kremlin envoy Kirill Dmitriev floated the tunnel idea late on Thursday after Putin spoke to Trump by phone and agreed to meet in Budapest.

Russia said Foreign Minister Sergei Lavrov and US Secretary of State Marco Rubio came to no agreement on a meeting during phone talks, casting a shadow over preparations for a planned summit between their presidents aimed at ending the war in Ukraine.

The Vienna Institute for International Economic Studies found Russia’s growth has slumped due to sky-high interest rates.