The US last week secretly shipped a new long-range missile system to Ukraine, and Ukrainian forces immediately used the weapons to attack a Russian military airfield in Crimea on April 17 and Russian troops in the country’s southeast overnight on Tuesday, according to a senior US official.

The US previously supplied Ukraine with a version of the Army Tactical Missile Systems — known as ATACMS — armed with wide-spreading cluster munitions that can travel 161km.

But Ukraine has long coveted the system’s longer-range version, with a range of about 307km, which can reach deeper into occupied Ukraine, including Crimea, a hub of Russian air and ground forces, and supply nodes for Moscow’s forces in the country’s southeast.

Overnight on Tuesday, Ukraine used the longer-range missiles to strike Russian troops in the port city of Berdyansk on the Sea of Azov, the senior US official said, speaking on the condition of anonymity to discuss operational matters.

On April 17, social media accounts in Ukraine reported large fires and explosions at a military airfield in Dzhankoi, Crimea, which the senior administration official said was also a long-range ATACMS target.

In a major policy shift, President Joe Biden secretly approved the decision to send more than 100 of the longer-range missiles in mid-February, the senior US official said, as well as more of the cluster munition variant.

They were part of a $300 million shipment of weapons to Ukraine in March, the first new aid package for the country since funding ran out in late December.