Russia fired its biggest ever drone barrage on Ukraine overnight, Kyiv said Monday, just hours after Donald Trump called Vladimir Putin "CRAZY" and warned Moscow risked new sanctions if it kept up its deadly bombardment.
The US President has been trying to broker an end to the three-year war but has failed to extract any major concessions from the Kremlin, despite repeated negotiations between his administration and Russia.
For three consecutive nights Russia has pummelled Ukraine with large-scale drone attacks, saturating its air defences and killing at least 13 people on Sunday, officials said.
In a rare rebuke of the Russian leader, Trump said on Truth Social late Sunday in Washington: "I've always had a very good relationship with Vladimir Putin of Russia, but something has happened to him. He has gone absolutely CRAZY!"
"I've always said that he wants ALL of Ukraine, not just a piece of it, and maybe that's proving to be right, but if he does, it will lead to the downfall of Russia!"
The Kremlin played down Trump's criticism on Monday, saying Putin was taking measures "necessary to ensure Russia's security".
"This is a very critical moment, which is fraught with emotional stress for everyone, as well as emotional reactions," Kremlin spokesman Dmitry Peskov told reporters.
Ukrainian President Volodymyr Zelensky said the attacks showed Russia had a sense of "impunity".
"The increase in Russian strikes should be met with increased sanctions," he said on social media.
Moscow's invasion of Ukraine, launched in February 2022, has killed tens of thousands of people, destroyed towns as well as cities and spurred the biggest crisis in relations with the West since the Cold War.
Kyiv did not report any immediate deaths from the latest drone attack, but said Russian shelling in the last 24 hours had killed a civilian man in the northern Sumy region.
Russia said Monday it had captured two border villages in Ukraine's north eastern Sumy region, where it has been mounting an offensive for weeks.
Earlier Sunday, Trump told reporters he was "not happy" about Russia's attacks on Ukraine and was "absolutely" considering increasing sanctions on Moscow.
AFP reporters in the capital Kyiv heard loud blasts from air defences early Monday.
Russia fired "355 Shahed-type drones" including decoys at Ukraine between Sunday night and early Monday, as well as nine cruise missiles, Ukraine's air force said.
Air force spokesman Yuriy Ignat told AFP it was the largest drone attack since Moscow's invasion began.
Air alerts in Kyiv lasted for six hours, officials said.
In the western Khmelnytsky region, Russian aerial attacks damaged 18 residential buildings, according to authorities.
A Russian attack also wounded a 14-year-old boy in the southern Odesa region, the region's governor said.
Diplomatic efforts to end the three-year war have stepped up a gear in recent weeks, with Russian and Ukrainian officials holding direct talks in Istanbul earlier this month for the first time in three years.
Both sides swapped 1,000 people each over the weekend in their biggest ever prisoner exchange, while Russia said it was preparing a document outlining its peace terms for ending the war.
But Moscow has repeatedly rejected proposals for a 30-day ceasefire from Kyiv and its Western allies, while grinding forward on the front line.
