The transfer last week came as Ukraine suffers from significant shortages of ammunition and US Republican lawmakers block new aid, but it does not address Kyiv's need for key items such as artillery and air defense munitions.

"The US government transferred over 5,000 AK-47s, machine guns, sniper rifles, RPG-7s and over 500,000 rounds of 7.62mm ammunition to the Ukrainian armed forces" on Thursday, the US Central Command (CENTCOM) said on social media.

"These weapons will help Ukraine defend against Russia's invasion" and are enough material to equip a brigade, it said,

The arms and ammunition were seized between May 2021 and February 2023 from four "stateless vessels" as they were being transferred from Iran's Revolutionary Guards to the Huthi rebels in Yemen, CENTCOM said.

The Huthis have been targeting ships in the Gulf of Aden and Red Sea since November 2023 in attacks they say are in solidarity with Palestinians in Gaza -- a major international security challenge that threatens a major shipping lane.

"Iran's support for armed groups threatens international and regional security, our forces, diplomatic personnel, and citizens in the region, as well as those of our partners. We will continue to do whatever we can to shed light on and stop Iran's destabilizing activities," CENTCOM said.