The U.S. will send $3.75 billion in military weapons and other aid to Ukraine and its neighbors on NATO’s eastern flank, the White House announced Friday, as Russia’s invasion of Ukraine grinds on.

The latest tranche of assistance will include for the first time Bradley armored vehicles for Ukraine. The armored carrier is used to transport troops to combat and is known as a “tank-killer” because of the anti-tank missile it can fire.

The biggest U.S. assistance package to date for Kyiv includes a $2.85 billion drawdown from the Pentagon’s stocks that will be sent directly to Ukraine and $225 million in foreign military financing to build the long-term capacity and support modernization of Ukraine’s military, according to the White House. It also includes $682 million in foreign military financing for European allies to help backfill donations of military equipment they’ve made to Ukraine.

“The war is at a critical point and we must do everything we can to help the Ukrainians resist Russian aggression,” White House press secretary Karine Jean-Pierre said in announcing the aid.

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The direct assistance for Ukraine includes 50 Bradleys as well as 500 anti-tank missiles and 250,000 rounds of ammunition for the carriers. The U.S. is also sending 100 M113 armored personnel carriers, 55 mine-resistant ambush protected vehicles, or MRAPS, and 138 Humvees, as well as ammunition for High Mobility Artillery Rocket Systems and air defense systems and other weapons and thousands of rounds of artillery, according to the Pentagon.

White House National Security Council spokesman John Kirby said the Bradleys will be particularly useful to Ukraine in ongoing heavy fighting in largely rural areas of eastern Ukraine.

“It’s very much tied to the war that we’re seeing on the ground right now and what we anticipate we’ll see throughout the winter months,” Kirby said.

Critics have complained that the U.S. has been too slow to provide key weapons such as the Bradleys and battle tanks like the Abrams, saying they could have helped in the fight last year.

At the Pentagon, Laura Cooper, the deputy assistant secretary for Russia and Ukraine, said this is the right time to provide the Bradley. “The Ukrainians have demonstrated a lot of growing proficiency in maintenance and sustainment,” she said.

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She added that the U.S.-led training set to begin later this month will enable troops to operate, maintain and repair the weapons and that providing tanks, such as the Pentagon’s more complex, gas guzzling, heavily armored M1 Abrams tank, would require more maintenance and other training.

The new U.S. package was detailed by the White House and Pentagon as Germany announced it would supply around 40 Marder armored personnel carriers to Ukraine in this year’s first quarter.

Germany announced its intention to send the Marder APCs following a phone call between Chancellor Olaf Scholz and President Joe Biden on Thursday.

“These 40 vehicles should be ready in the first quarter already so that they can be handed over to Ukraine,” Scholz’s spokesman, Steffen Hebestreit, told reporters in Berlin. Germany plans to train Ukrainian forces to use the vehicles, and Hebestreit said experts expect that process to take around eight weeks.

Germany has already given significant military aid, including howitzers, Gepard self-propelled anti-aircraft guns and an IRIS-T surface-to-air missile system, with three more of those set to follow this year.

Scholz has long been wary of pressure to supply the Marder and other, heavier Western-made vehicles such as tanks, insisting that Germany wouldn’t go it alone with such deliveries. Officials noted that other countries hadn’t supplied any. But this week, France, the U.S. and Germany all announced plans to send comparable armored vehicles that fall short of tanks.

Germany last year championed deals in which eastern NATO allies sent familiar Soviet-era equipment to Ukraine, with Germany in turn supplying those countries with more modern Western-made equipment.

Hebestreit said there had been talks with the U.S. and others since mid-December on how to support Ukraine going forward. He said the possibility of supplying Soviet-produced equipment is “slowly coming to an end,” while the situation in Ukraine is changing with massive Russian strikes on infrastructure and fighting that could increase when the weather warms up.

Ukraine and a number of German lawmakers inside and outside Scholz’s governing coalition also have called for Germany to deliver Leopard 2 battle tanks. Advocates of delivering the Leopard were cheered by the move on Marder APCs and vowed to keep pressing the point.

But Hebestreit said that battle tanks weren’t an issue in Thursday’s call between Scholz and Biden. He said Germany will stick to its principles of supporting Ukraine as strongly as possible, while not going it alone on weapons supplies and ensuring that NATO doesn’t become a party to Russia’s war in Ukraine.

Germany also said Thursday that it will follow the U.S. in supplying a Patriot air defense missile battery to Ukraine. That was at the request of the U.S. and also is expected in the first quarter, Hebestreit said.

It comes on top of Patriot systems that Germany has sent or plans to send to Slovakia and Poland.