Donald Trump has revealed Vladimir Putin told him "very strongly" in a phone call that he will respond to Ukraine's audacious weekend drone attack on Russian airfields.
The US president said in a social media post that "it was a good conversation, but not a conversation that will lead to immediate peace."
The call on Wednesday that lasted for an hour and 15 minutes was Mr Trump's first known with the Russian President since May 19.
Writing on his Truth Social platform Trump said: “We discussed the attack on Russia’s docked airplanes by Ukraine, and also various other attacks that have been taking place by both sides,” Trump said. “It was a good conversation, but not a conversation that will lead to immediate peace.”
“President Putin did say, and very strongly, that he will have to respond to the recent attack on the airfields,” Trump said.
Ukraine's Security Service have given more details about the drone strikes on Russian air bases, which it claimed destroyed or damaged 41 Russian aircraft, including strategic bombers.
The agency claimed the planes struck included A-50, Tu-95, Tu-22, Tu-160, An-12, and Il-78 aircraft, adding that artificial intelligence helped guide the drones thousands of kilometres from Ukraine.
It also said it set off an explosion on Tuesday on the seabed beneath the Kerch Bridge, a vital transport link between Russia and illegally annexed Crimea, claiming it caused damage to the structure. But Kremlin spokesperson Dmitry Peskov said on Wednesday that there was no damage.
The White House is growing frustrated with both Russia and Ukraine and the inability to agree a ceasefire as the war continues to rage.
Russia's Defence Ministry said on Wednesday that its troops have taken control of another village in Ukraine's northern Sumy region, on the border with Russia.
Mr Putin announced on May 22 that Russian troops aim to create a buffer zone that might help prevent Ukrainian cross-border attacks. Since then, Russia's Ministry of Defence claims its forces have taken control of nine Sumy villages.
Trump did not say in his post that the White House has demanded constraint in Russia’s retaliation to the Ukriainian strikes on the Russian bombers, or that he had tried to dissuade Putin from taking action. There is no indication that Trump had spoken to his Ukrainian counterpart, President Zelensky.
Mr Trump says part of his call with Mr Putin, that media had not been made aware of prior to it happening, was also focused on Iran and "the fact that time is running out on Iran's decision pertaining to nuclear weapons, which must be made quickly!"
Mr Trump said in a post on his social media site that he told Russia's president "that Iran cannot have a nuclear weapon and, on this, I believe that we were in agreement".
He said Mr Putin suggested "that he will participate in the discussions with Iran" and could perhaps "be helpful in getting this brought to a rapid conclusion".
Mr Trump previously boasted that a major announcement on Iran was coming - but none has materialised.
He suggested in his latest post that Iran has been slow-walking their decision "and we will need a definitive answer in a very short period of time!".