WASHINGTON, DC, United States (AP) — President Joe Biden said Wednesday the US is sending more anti-aircraft, anti-armour weapons and drones to Ukraine to assist in its defence against Russia.

The president’s comments came as he formally announced his Administration was sending an additional $800 million in military assistance to Ukraine, making a total of $2 billion in such aid sent to Kyiv since Biden took office more than a year ago. About $1 billion in aid has been sent in just the last week.

“We’re going to give Ukraine the arms to fight and defend themselves through all the difficult days ahead,” Biden said.

Biden spoke hours after Ukrainian President Volodymyr Zelenskyy delivered a video address to members of US Congress in which he made an impassioned plea for the US and West to provide more help to save his young democracy than world leaders have so far pledged to provide.

The Ukrainian president recalled the horror of Pearl Harbour and the September 11, 2001 terror attacks in appealing Wednesday to the US Congress to do more to help Ukraine’s fight against Russia, but he acknowledged the no-fly zone he has sought to “close the sky” to airstrikes on his country may not happen.

Livestreamed into the Capitol complex, Zelenskyy said the US must sanction Russian lawmakers and block imports. But rather than an enforced no-fly zone that the White House has resisted, he instead sought other military aid to stop the Russian assault.

For the first time in a public address to world leaders, he showed a packed auditorium of lawmakers a graphic video of the destruction and devastation his country has suffered in the war, along with heartbreaking scenes of civilian casualties.

“We need you right now,” Zelenskyy said. “I call on you to do more.”

Lawmakers gave him a standing ovation, before and after his short remarks, which Zelenskyy began in Ukrainian through an interpreter but then switched to English in a heartfelt appeal to help end the bloodshed.

“I see no sense in life if it cannot stop the deaths,” he said.

Nearing the three-week mark in an ever-escalating war, Zelenskyy has used the global stage to implore allied leaders to help stop the Russian invasion of his country. The young actor-turned-president often draws from history, giving weight to what have become powerful appearances.

President Joe Biden’s Administration has stopped short of providing a no-fly zone or the transfer of military jets from neighboring Poland as the US seeks to avoid a direct confrontation with nuclear-armed Russia.

The White House, meanwhile, is considering giving Ukraine access to US-made Switchblade drones that can fly and strike Russian targets, according to a separate person familiar with the matter who was not authorized to speak publicly.

Zelenskyy has emerged as a heroic figure at the centre of what many view as the biggest security threat to Europe since World War II. Almost three million refugees have fled Ukraine, the fastest exodus in modern times.

Wearing his now trademark army green T-shirt, Zelinskyy began the remarks to his “American friends” by invoking the destruction the US suffered in 1941 when Japan bombed the naval base at Pearl Harbour in Hawaii, and the 2001 attacks on the World Trade Center and the Pentagon by militants who commandeered passenger airplanes to crash into the symbols of Western democracy and economy.

“Remember Pearl Harbor? … Remember September 11?” Zelenzkyy asked. “Our countries experience the same every day right now.”

Senator Angus King, the Maine independent, said there was a “collective holding of the breath” in the room during Zelenskyy’s address. Republican Senator Lisa Murkowski of Alaska said, “If you did not look at that video and feel there is an obligation for not only the United States but the free countries of the world to come together in support of Ukraine, you had your eyes closed.” Majority Whip Dick Durbin called the address heartbreaking and said, “I’m on board with a blank check on sanctions, just whatever we can do to stop this Russian advance”.

Outside the Capitol demonstrators held a large sign lawmakers saw as they walked back to their offices. “No Fly Zone=World War 3.”

The Ukrainian president is no stranger to Congress, having played a central role in Donald Trump’s first impeachment. As president, Trump was accused of withholding security aid to Ukraine as he pressured Zelenskyy to dig up dirt on political rival Biden. Zelenskyy spoke Wednesday from a giant screen to many of the same Republican lawmakers who declined to impeach or convict Trump, but are among the bipartisan groundswell in Congress now clamouring for military aid to Ukraine.

He thanked the American people, saying Ukraine is grateful for the outpouring of support, even as he urged Biden to do more.

“You are the leader of the nation. I wish you be the leader of the world,” he said “Being the leader of the world means being the leader of peace.”

It was the latest visit as Zelenskky uses the West’s great legislative bodies in his appeals for help, invoking Shakespeare’s Hamlet last week at the British House of Commons asking whether Ukraine is “to be or not to be” and appealing Tuesday to “Dear Justin” as he addressed the Canadian Parliament and Prime Minister Justin Trudeau. He often pushes for more help to save his young democracy than world leaders have so far pledged to provide.

To Congress, he drew on the image of Mount Rushmore and told the lawmakers that people in his country want to live their national dreams just as they do.

“Democracy, independence, freedom.”

Biden has insisted there will be no US troops on the ground in Ukraine and has resisted Zelenskyy’s relentless pleas for warplanes as too risky, potentially escalating into a direct confrontation with nuclear-armed Russia.

“Direct conflict between NATO and Russia is World War III,” Biden has said.

Zelenskyy appeared to acknowledge the political reality.

“Is this to too much to ask to create a no fly zone over Ukraine?” he asked, answering his own question. “If this is too much to ask, we offer an alternative,” he said, calling for weapons systems that would help fight Russian aircraft.

Already the Biden Administration has sent Ukraine more than 600 Stinger missiles, 2,600 Javelin anti-armuor systems, unmanned aerial system tracking radars, grenade launchers, 200 shotguns, 200 machine guns and nearly 40 million rounds of small arms ammunition, along with helicopters, patrol boats, satellite imagery and body armour, helmets, and other tactical gear, the US official said.

Congress has already approved $13.6 billion in military and humanitarian aid for Ukraine, and the newly announced security aid will come from that allotment, which is part of a broader bill that Biden signed into law Tuesday.