The money adds to $2.4 billion in U.S. aid already authorized for the fiscal year, much of it weaponry. Of the new package, $800 million will go toward arms.

Biden also said no Russian-flagged ships would be allowed into U.S. ports, following a move by European countries.

“We’re in a critical window now of time where they’re going to set the stage for the next phase of this war,” Biden said. “And the United States and our allies and partners are moving as fast as possible to continue to provide Ukraine the weapons they need, the equipment their forces need to defend their nation.”

Biden last week announced a package of aid that he said provided “new capabilities include artillery systems, artillery rounds, and armored personnel carriers,” as well as the transfer of additional helicopters.

Before his remarks, Biden met with Ukraine’s prime minister, Denys Shmyhal, at the White House.

More than half a dozen flights bearing U.S. equipment will land in the Ukraine region “shortly,” White House Press Secretary Jen Psaki said Wednesday. That includes long-range weapons Kyiv is expected to need as the war shifts to Ukraine’s eastern Donbas region, which Russia seeks to capture after its offensive on Kyiv failed.

“It requires different kinds of weapons to be more effective,” Biden said Thursday. He said the U.S. will provide “dozens” of howitzers and 144,000 artillery shells.

But he warned that money already authorized by Congress to support Ukraine’s defense is “almost exhausted,” and that the administration would ask for more. He didn’t say how much he’d request. 

Congress included $13.6 billion for Ukraine aid in a full-year spending bill for the government that passed in March.

The new request, which Biden said he’ll send to Congress next week, is intended “to sustain Ukraine for the duration of this fight” and “to keep weapons and ammunition flowing without interruption to the brave Ukrainian fighters, to continue to deliver economic assistance to the Ukrainian people.”

Biden also called the battle of Kyiv “a historic victory for the Ukrainians. It was a victory for freedom, won by the Ukrainian people with unprecedented assistance by the United States and our allies and our partners.”

Ukrainian forces fought off Russia’s advance on the country’s capital earlier this month. Moscow’s withdrawal revealed widespread civilian killings and other atrocities in areas it had occupied, though the Kremlin has denied responsibility. 

Earlier Thursday, senior administration officials detailed plans to allow as many as 100,000 Ukrainians to come to the U.S. for two years, provided they have family or another sponsor in the country.

The program will provide an “expedient channel” for migration from Ukraine to the U.S., Biden said. “This program will be fast, it will be streamlined,” he said.

Ukrainian nationals who travel to Mexico and try to enter the U.S. through the southern border will not receive any preference, one U.S. official said. Roughly 50,000 Ukrainians have already entered the U.S. via Mexico in recent months, the official said.

An online portal to apply for the program will open April 25.