The United States announced a new $400 million security aid package for Ukraine on Friday that features various types of ammunition for Kyiv's forces.

"This military assistance package includes more ammunition for US-provided HIMARS and howitzers, which Ukraine is using so effectively to defend itself," the US State Department said in a statement, referring to precision rocket systems and artillery pieces.

The package also includes ammunition for Bradley Infantry Fighting Vehicles, as well as Armored Vehicle Launched Bridges for use in crossing rivers and other water obstacles.

The United States has spearheaded the push for international support for Ukraine, quickly forging an international coalition to back Kyiv after Russia invaded in February 2022 and coordinating aid from dozens of countries.

Kyiv has pushed for some items that its international supporters have been reluctant to provide, including Patriot air defence systems and advanced heavy tanks -- which were eventually promised -- and others such as Western fighter aircraft, which have not been so far.

Ukraine's supporters are training the country's troops on new weapons that are being provided, and US forces started a program focused on larger-scale manoeuvres in January.