Biden announces $800 million in military aid for Ukraine.

WASHINGTON — President Biden said on Wednesday that the United States would send $800 million in additional military assistance to Ukraine, shortly after the country’s president, Volodymyr Zelensky, delivered an impassioned virtual address to Congress in which he appealed for more help in staving off Russia’s invasion.

“This new package on its own is going to provide unprecedented assistance to Ukraine,” Mr. Biden said, adding that the Russian invasion was producing “appalling devastation and horror” in that country.

“The American people are answering President Zelensky’s call for more help, more weapons for Ukraine,” he said.

But Mr. Biden stopped well short of responding to the more direct military intervention that Mr. Zelensky has repeatedly requested, including for the United States and NATO to enforce a no-fly zone over Ukraine.

In his dramatic address to American lawmakers hours earlier, Mr. Zelensky showed a gruesome video of the Russian attacks on Ukrainian cities and pleaded for additional military aid, a no-fly zone and more severe sanctions on Russia. He described the threat his nation faced as an attack on the democratic values championed by the United States.

Speaking from the White House, Mr. Biden condemned what he called a “God-awful” invasion that is an “outrage to the world.” And he hailed Mr. Zelensky’s courage.

“He was convincing,” Mr. Biden said of the Ukrainian president’s address to Congress, calling it a “significant speech.”

“He speaks for a people who have shown remarkable courage and strength in the face of brutal aggression,” Mr. Biden said.

Mr. Biden has pledged to enhance Ukraine’s ability to fight and to defend its capital, Kyiv, and other besieged cities while also trying to avoid steps that could lead to a direct military confrontation with Russia and a broader war in Europe.

White House officials said the $800 million that Mr. Biden announced was part of the spending package he signed on Tuesday that included $14 billion in aid for Ukraine.

The United States last week announced $200 million in security aid for Ukraine. In February, it approved a $350 million arms package.

The weapons provided to Ukraine from the United States have included at least 600 Stinger antiaircraft missiles and about 2,600 Javelin antitank missiles, according to a senior White House official. But Ukraine says it needs sophisticated antimissile systems.

The United States has also provided five Mi-17 helicopters, three patrol boats and 70 other vehicles of various kinds, plus small arms, tactical gear and military medical equipment, the White House official said. The weapons come from existing U.S. military stockpiles in Europe, the official said, and are flown into neighboring countries like Poland and Romania, where they are shipped overland into western Ukraine.

Zolan Kanno-Youngs, David E. Sanger and Katie Rogers contributed reporting.