US president Donald Trump’s claims that Vladimir Putin has gone “absolutely crazy” are down to “emotional overload”, the Kremlin has claimed.

Mr Trump on Sunday said his Russian counterpart Mr Putin had "gone absolutely CRAZY" by unleashing a massive aerial attack on Ukraine and said he was weighing new sanctions on Moscow, though he also scolded Ukrainian president Volodymyr Zelensky.

“We are really grateful to the Americans and to president Trump personally for their assistance in organising and launching this negotiation process,” Kremlin spokesperson Dmitry Peskov said when asked about Mr Trump's remarks about Mr Putin.

“Of course, at the same time, this is a very crucial moment, which is associated, of course, with the emotional overload of everyone absolutely and with emotional reactions,” Mr Peskov said.

Germany and other major allies are no longer imposing any range restrictions on weapons supplied to Ukraine as it fights the Russian invasion, its new chancellor Friedrich Merz said.

The German leader said that "there are no longer any range restrictions for weapons that have been delivered to Ukraine — neither by the British, nor by the French, nor by us, and not by the Americans either."

"That means Ukraine can also defend itself by, for example, attacking military positions in Russia," Mr Merz said at a forum organised by WDR public television.

"Until a while ago, it couldn't. — It can now," he said.

"We call this 'long-range fire' in jargon, also supplying Ukraine with weapons that attack military targets in the hinterland," he added.

Mr Merz did not elaborate, and it wasn't clear whether he was referring to the easing of restrictions on longer-range weapons late last year.

Germany, along with the UK and France, has plunged into diplomatic efforts to try to secure a ceasefire and keep Western support for Ukraine intact.

Ukrainian president Volodymyr Zelensky has said the hundreds of Russian attacks on his country are a “political choice” made by Vladimir Putin.

Speaking in his nightly video address, Mr Zelensky said: “Over 900 attack drones launched against Ukraine in just three days, along with ballistic and cruise missiles. There is no military logic in this, but it is a clear political choice of Russia – the choice to keep waging war.”

“We can see from the information obtained by intelligence and from open-source data that Putin and his entourage do not plan to end the war.”

Mr Zelensky has asked the Russian leader to “start respecting those he talks to”.

“For now, he is simply playing games with diplomacy and with diplomats. That must change,” Mr Zelensky said.