The U.S. unveiled $2.6 billion worth of military assistance that includes three air surveillance radars, anti-tank rockets and fuel trucks, the Pentagon announced on Tuesday, as Ukraine prepares a spring offensive against Russian forces.

Ukrainian President Volodymyr Zelenskyy on Tuesday told the U.S. National Governors Association that the United States could protect its values by helping Ukraine.

"Our cooperation will allow for the new enhancement of your security, for our economy and yours, for jobs in both our countries," Zelenskyy said by video link.

"The main thing is not to lose time, not to lose the chance we have. Act now, help now. Ukrainians act so that Americans don't have to fight - and together we gain new strength for our countries," he continued.

The Russian embassy in Washington reacted to the announcement by accusing the United States of wanting to drag out the conflict as long as possible, Russian news agency TASS said.

"The decision to supply weapons to Kyiv is a step towards escalating the Ukrainian crisis and increasing the number of civilian casualties," it cited an embassy statement as saying.

The weapons aid package comprised $2.1 billion from Ukraine Security Assistance Initiative (USAI) funding which allows President Joe Biden's administration to buy weapons from industry rather than from U.S. weapons stocks.

The USAI package included additional munitions for NASAMS air defenses that the U.S. and allies have given to Kyiv, precision aerial munitions, Soviet-era GRAD rockets, anti-tank rockets, armored bridging systems used in assaults, and 105 fuel trailers, along with funding for training and maintenance.

The remaining $500 million came from Presidential Drawdown Authority funds, which allows the president to take from current U.S. stocks in an emergency.

That segment of the package included a half a dozen types of munitions, including munitions for Patriot air defense systems, tank munitions, and High Mobility Artillery Rocket Systems (HIMARS).

Last month, Leopard 2 battle tanks pledged by Germany and Portugal reached Ukraine. The package announced on Tuesday includes 61 heavy fuel tankers and recovery vehicles to help disabled heavy equipment like tanks.

The U.S. has now pledged more than $35.2 billion worth of security assistance to Ukraine since February last year. On Monday, Ambassador Julianne Smith, the U.S. permanent representative to NATO, said that Washington expects Ukraine "to put forward or begin some sort of their own spring offensive in the weeks ahead."

(Cover: A U.S. M142 HIMARS fires salvoes during the "African Lion" military exercise in the Grier Labouihi region of southeastern Morocco, June 21, 2022. /CFP)