US President Joe Biden has ordered a new $600 million arms package to help the Ukrainian military battle Russia.
US Secretary of State Antony Blinken on Thursday said Mr Biden had authorised the 21st transfer of weapons from US stocks to Ukraine since September 2021.
"This $600m drawdown includes additional arms, munitions and equipment from US Department of Defence inventories," Mr Blinken said.
"This drawdown will bring the total US military assistance for Ukraine to approximately $15.8 billion since the beginning of this administration."
He said the new package was part of Mr Biden's pledge to support the people of Ukraine "for as long as it takes".
"With admirable grit and determination, the people of Ukraine are defending their homeland and fighting for their future," Mr Blinken said.
"The United States is providing Ukraine military assistance alongside our allies and partners from more than 50 countries to support its defence.
"The capabilities we are delivering are carefully calibrated to make the most difference on the battlefield and strengthen Ukraine’s hand at the negotiating table when the time is right."
Reuters earlier reported that the order from Mr Biden was first revealed in a memo to the State Department.
He authorised the assistance using his Presidential Drawdown Authority, which allows him to transfer excess weapons from US stocks.
The memo does not detail how the money would be used, but sources told Reuters it was expected the package would contain munitions, including more High Mobility Artillery Rocket Systems, or Himars.
The package would also include ammunition for howitzers, the sources said.
The memo said the money would also be used for military education and training.