PRESIDENT Donald Trump says mad Vladimir Putin made a "mistake" with the double missile strike that killed 34 people and wounded at least 119.
Following the heinous attack on Sumy, Ukrainian President Volodymyr Zelensky has invited the Republican to visit his country before any deal is reached with Russia to end the war.
Trump denounced the strike as “terrible” and a “horrible thing” - but declined to directly blame Putin or Russia.
He instead suggested that the attack it was an error to fire two Iskander-M missiles into a city centre crowded with civilians.
“I was told they made a mistake,” he said of one of the most shocking strikes of the war, adding: “Ask them.”
“Millions of people are dead that should be alive.
“Cities are being destroyed all over Ukraine. The whole culture is gone or certainly very severely hurt.”
Meanwhole Zelensky warned starkly of World War III if Putin is not stopped.
He accused the US of being blinded by Russian propaganda, waring Putin's ultimate goal is “to revive the Russian empire and return the territories that are now under NATO protection” - including Estonia, Latvia, Lithuania, and possibly Finland and Poland, as well as Ukraine, and central Asian states such as Kazakhstan.
“Considering all this, I believe that this could escalate into a world war,” said Zelensky, warning: “There will be no safe place for anyone.”
He urged Trump to stop believing Putin’s claims that he wants peace and instead to visit Ukraine and see for himself the havoc wrought by the Russian dictator.
“See, and then let's move forward with a plan to end the war. You will understand who you have a deal with. You will understand what Putin did.”
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Zelensky said: “Unfortunately, I believe that Russian narratives prevail in the United States.
“How can you witness our losses and our suffering, understand what the Russians are doing, and at the same time believe that they are not the aggressors, that they did not start this war?
“This speaks to the enormous influence of Russia's information policy on America, on US policy and US politicians.”
World leaders slammed the Palm Sunday slaughter, with Zelensky branding Putin "b***ard" for deliberately targeting civilians.
Grieving relatives were seen weeping over the bodies of their loved ones lying in the street.
Local military officials said Russia had used vicious cluster munitions to maximise the slaughter.
They said: “It exploded in the air, the most victims were in the trolley bus — almost all passengers died. This is a trolleybus of death.”
Keir Starmer said he was "appalled" by the "horrific attacks on civilians in Sumy" and his thoughts to the victims.
He said that Zelensky has "shown his commitment to peace" and that "Putin must now agree to a full and immediate ceasefire without conditions".
Ukraine's foreign minister, Andrii Sybiga, condemned the attack as a "war crime".
He said: “We are already sharing detailed information about this war crime with all our partners and international institutions.
“We call on all capitals and headquarters to respond decisively.
“For the second month in a row, Russia refuses to accept the US proposal for a complete ceasefire, which Ukraine unconditionally accepted on March 11.
“Instead, Russia is intensifying terror."
Andriy Yermak, Zelensky's chief of staff, said: "The Russians hit the city of Sumy with missiles, killing civilians."
Andriy Kovalenko, a disinformation security official, noted the strike's timing after the visit of US envoy Steve Witkoff to Moscow.
He said: "Russia is building all this so-called diplomacy [...] around strikes on civilians."
The Palm Sunday attack comes a week on from Russian rocket strikes on Ukraine's capital Kyiv - which Zelensky said breached the naval ceasefire.