From the besieged capital of Ukraine, Volodymyr Zelensky pleaded with the US Congress to do more to save his nation and preserve democratic values, in an emotional appeal that invoked the painful memories of Pearl Harbor and 911 and echoed Martin Luther King’s call for a more peaceful future.

The remarks to members of both chambers of Congress come on day 21 of the battle for Ukraine’s survival under an intensifying assault from Russia, that Zelensky said had killed more than 100 children.

Wearing his army green T-shirt, with a Ukrainian flag draped behind him, Zelensky was direct: “I call on you to do more.

“The destiny of our country is being decided,” he told the Congress. “We need you right now.”

Appearing by video link into the Capitol, Zelensky asked the US to send more military aid and to impose harsh new sanctions on Russian lawmakers. Accepting that a no-fly zone was unlikely, he asked the packed auditorium of lawmakers to consider an “alternative”, including more aircraft and better weaponry, to help Ukraine “close the skies”.

In referencing Pearl Harbor and 9/11, attacks that came from the sky, he asked members of Congress to imagine Ukraine’s experience: “Our country experiences this every day, right now, at this moment, every night for three weeks now.”

He also played a video that showed Ukraine as it was before Russia’s invasion, and the horror that has been wrought on its people since.

Before and after he spoke, lawmakers gave him a standing ovation. Zelenskiy placed his hand over his heart in gratitude. He delivered most of his speech in Ukrainian, but made a final appeal in English.

“I see no sense in life if it cannot stop the deaths,” he said, appearing emotional as he spoke of the children who has died in the bombardment.

Lawmakers left the auditorium visibly moved by the remarks of the embattled Ukrainian leader, as he rallies his nation and the world from the frontline of what many believe is the most dangerous security threat to Europe since the end of the second world war.

Senator Ben Sasse, a Republican from Nebraska, implored the US to send more military assistance.

“They’re fighting for the free world,” he said. “We’re a superpower. We should act like it.”

Joe Biden has said he speaks to the Ukrainian leader privately nearly every day. But on Wednesday, before the US president was due to speak, Zelensky asked him publicly to do more to stop the bloodshed.