Ukrainian President Volodymyr Zelenskyy delivers a virtual address to Congress by video at the Capitol in Washington, Wednesday, March 16, 2022. (Sarah Silbiger, Pool/AP)

WASHINGTON — Ukrainian President Volodymyr Zelenskyy made an emotional appeal to Congress on Wednesday for air cover against invading Russian forces as the U.S. unleashed a new wave of military support for his embattled country.

“Russia has turned the Ukrainian sky into a source of death for thousands of people,” he told U.S. lawmakers in a historic address by a wartime leader. “This is a terror that Europe has not seen for 80 years and we are asking for a reply, for an answer.”

The White House responded hours later with $800 million in new military assistance to Ukraine, including anti-aircraft weapons to defend Ukrainian air space from Russian attacks. The U.S. aid also included anti-armor weapons, small arms, ammunition, drones and other equipment. Combined with the new package, the U.S. has sent about $2 billion in military support to the war-torn country in the past year.

However, Zelenskyy’s most urgent demand, a no-fly zone over Ukraine, was not met. President Joe Biden refuses to protect the Ukrainian sky because it would put the U.S. military and NATO in direct conflict with Russian forces and potentially lead to a world war.

Zelenskyy has remained persistent in his plea for the zone, repeating his request to the Canadian Parliament, Britain’s House of Commons and the European Parliament this month. To convince U.S. lawmakers to “close the sky” over Ukraine, Zelenskyy played a graphic video showing the human toll of Russia’s furious assault on its neighbor.

Members of Congress were visibly moved by the footage of bombs exploding in Ukrainian cities, bodies being placed into mass graves and bloodied civilians receiving medical treatment. Sen. Ben Sasse, R-Neb., urged every mother and father to watch the video with their families.

“Everybody knows who Zelenskyy is. The man has the courage of his convictions,” he said. “Everybody knows who [Russian President Vladimir] Putin is. He believes in murdering women and children — you can see it in the video.”

Zelenskyy asked lawmakers on Wednesday to remember the darkened skies during Pearl Harbor and the terrorist attacks of Sept. 11, 2001. He said Ukraine is experiencing that same carnage “every day, right now at this moment.”

If the U.S. cannot close the skies to Russian bombardment, Zelenskyy offered an alternative: send Kyiv air-defense systems and aircraft. He told lawmakers to pursue sanctions against every Russian politician who has not denounced the war and pressure companies in their districts and states to leave the Russian market.

Ukrainian President Volodymyr Zelenskyy receives a standing ovation as he appears via videoconference to make an address to Parliament, in the House of Commons on Parliament Hill in Ottawa, on Tuesday, March 15, 2022. (Justin Tang/AP)

Invoking Martin Luther King Jr.’s “I Have a Dream” speech, Zelenskyy said, “I have a need.”

Zelenskyy addressed lawmakers in Ukrainian, sitting in his trademark military green T-shirt beside a Ukrainian flag. But he made his last appeal in English, speaking directly to Biden and referencing the historic standing of the U.S. as the leader of the free world.

“To be the leader of the world means to be the leader of peace,” he said.

Zelenskyy’s virtual speech to lawmakers came amid backlash in Congress to the White House’s decision last week to nix a delivery of fighter jets from NATO ally Poland to Ukraine. Poland offered to provide its neighbor with the Soviet-era jets if the U.S. acted as a middleman for the transfer — a proposal U.S. officials feared Russia would interpret as an escalation of the war.

Democratic and Republican lawmakers have shown strong support for pouring military and humanitarian aid into Ukraine, approving a $14 billion assistance package last week for the battered country. They overwhelmingly rallied around Zelenskyy on Wednesday, touched by Ukraine’s fight for democracy and survival.

“President Zelenskyy’s steadfast leadership and unwavering resolve has not only inspired the fighting spirit among Ukrainians as they defend their land, freedom and future, but also people throughout the world watching Ukraine hold the line for liberal democracies around the globe,” said Sen. Jeanne Shaheen, D-N.H. “It is clear that more must be done to assist Ukraine and hold Putin to account.”

Sen. Rick Scott, R-Fla., agreed with Zelenskyy’s request to sanction Russian politicians and he said American companies should pull out of Russia and its ally Belarus. He urged Congress to pass a bill to end normal trade relations with Russia and ban all Russian imports.

“The United States has the power to give Ukraine what it needs to win and ensure Putin and his thugs personally feel the pain of this ruthless and unlawful invasion,” Scott said. “We must use it.”

Scott and 41 other Republican senators implored President Biden last week to boost Ukrainian air power through the transfer of planes. On Sunday, nearly 60 members of the House’s bipartisan Problem Solvers Caucus asked the White House to reconsider rejection of the Polish fighter jet deal.

“Russia’s advantage in this domain could soon develop into air dominance if the Ukrainians do not receive necessary military aid,” members wrote in a statement. “This is a pragmatic solution to expeditiously provide the Ukrainians with aircraft that Ukrainian pilots have flown and their service members can maintain.”

Air Force Gen. Tod Wolters, the commander of U.S. forces in Europe, has spoken out against the Polish offer, saying it would not “appreciably increase the effectiveness of the Ukrainian air force.” The U.S. and its NATO allies should instead supply Ukraine with more anti-tank and air-defense systems, he said.

“The Ukrainians are making excellent use of these weapons now,” Wolters said in a statement. “Although Russian air capabilities are significant, their effectiveness remains limited due to Ukrainian strategic, operational and tactical ground-based air defense systems.”

The air space over Ukraine remains contested, according to defense officials, with Russia failing to achieve air superiority three weeks into its invasion of Ukraine. Russia’s military far outnumbers Ukraine’s, however, and its forces still have 90% of combat power available, a U.S. defense official said Tuesday.

There was no broad support on Capitol Hill on Wednesday to institute a no-fly zone despite Zelenskyy's impassioned appeal. Though sympathetic to Ukraine's plight, lawmakers remained jittery that directly involving American or NATO forces would plunge the U.S. into a war with another nuclear power.

“Zelenskyy called on us to be leaders of the world and the leaders of peace,” said Rep. Sara Jacobs, D-Calif. “That means not getting the world — and the billions of civilians who would be impacted — into a nuclear war.”