A $400 million security aid package to Ukraine is expected to be announced on Friday, two US officials told CNN.
The package will include ammunition for HIMARS rocket launchers and various artillery systems such as 155 mm and 105 mm.
It will also, for the first time, include a system used to build bridges, officials said.
This security assistance will come directly from US stockpiles under the President's Spending Reduction Authority (PDA), which means weapons and equipment can be quickly delivered to Ukraine.
On Thursday, John Kirby, the National Security Council's strategic communications coordinator, said the US would announce another round of aid to Ukraine, including HIMARS ammunition and artillery, but did not specify how much.
Last week, the US announced $2 billion in aid through the Ukraine Security Assistance Initiative (USAI), which contracts with industry to purchase materials.