The United States will provide $1.85 billion in additional military assistance for Ukraine, including a transfer of the Patriot Air Defense System, President Joe Biden and Secretary of State Antony Blinken said on Wednesday.

The announcement came as Ukrainian President Volodymyr Zelenskyy arrived in Washington for his first known overseas trip since the Russia-Ukraine conflict began 300 days ago.

Biden welcomed Zelenskyy to the White House for a bilateral meeting Wednesday, pledging the United States would "continue to strengthen Ukraine's ability to defend itself, particularly air defense."

The Patriot system is "a defensive system, it's not escalatory, it's defensive," Biden said in a joint news briefing with Zelenskyy. "We'd love not to have them used, just stop the attacks," Biden added.

The assistance includes a $1 billion drawdown to provide Ukraine with "expanded air defense and precision-strike capabilities" and $850 million in security assistance, Blinken said in a separate statement.

Zelenskyy said in the news conference that the U.S. promise to provide the Patriot system was "an important step in creating an effective air shield."

The United States has committed about $21.2 billion in military assistance to Kyiv since Russia launched its "special military operation" on February 24.

The Patriot is considered to be one of the most advanced U.S. air defense systems and offers protection against aircraft, cruise and ballistic missiles. It typically includes launchers along with radar and other support vehicles.

Russia said last week that U.S. plans to supply Patriot missile defense systems to Ukraine were a "provocation" and a further expansion of U.S. military involvement in the Ukraine conflict.

In a Wednesday speech to defense chiefs in Moscow, Russian President Vladimir Putin said the Russian army must learn from and fix the problems it had suffered in Ukraine, and promised to give the military whatever it asks for.

(With input from Reuters)