Six of the UK's Stormer armoured vehicles have arrived on the frontline in Ukraine.
Ukraine's Operational Command South posted on Facebook to mark their arrival on the frontline.
The Stormer can be used as a mobile platform to transport the high-velocity Starstreak missile system.
It has a 5.5 km max range, with eight missiles ready to fire and nine replacements, designed for defence against low-level attack aircraft and helicopters.
A panoramic weapon sight sits at the front of the vehicle, according to the Army.
The US government has announced it will send additional high mobility artillery rocket systems and a "substantial number" of Phoenix Ghost unmanned aerial systems.
Four additional HIMARS systems (to bring Ukraine's total to 16), four command post vehicles, more anti-armour weaponry, spare parts and 36,000 rounds of 105mm ammunition will also be sent from America, the US Department of Defense explained.
Watch: What is the Starstreak anti-air weapons system?
"This is ammunition that is actually going to support a donation that the United Kingdom is making of howitzers, and this is something that we do quite frequently where we match countries that maybe have one part of a capability with another donor country to create a complete capability for the Ukrainians," a senior US defence official said.
The UK has provided thousands of weapons to Ukraine's armed forces since Russia's invasion in late February 2022.
Western countries began cautiously, supplying helmets and flak jackets, before limiting supplies to defensive weapons.