Ukraine for the first time has begun using long-range ballistic missiles provided secretly by the United States, bombing a Russian military airfield in Crimea last week and Russian forces in another occupied area overnight, American officials said on Wednesday.
Long sought by Ukrainian leaders, the new missiles give Ukraine nearly double the striking distance, up to 190 miles, that it had with the mid-range version of the weapon that it received from the US last October.
One of the officials said the US is providing more of these missiles in a new military aid package signed by President Joe Biden on Wednesday.
Mr Biden approved delivery of the long-range Army Tactical Missile System, known as ATACMS, in early March, and the US included a “significant” number of them in a 300 million dollar (£241 million) aid package announced at the time, one official said.
The two US officials would not provide the exact number of missiles given last month or in the latest aid package.
Ukraine has been forced to ration its weapons and is facing increasing Russian attacks.
“The key now is speed,” Ukraine President Volodymyr Zelensky tweeted. He urged quick deployment of the hardware that Kyiv expects to receive in the coming weeks and months.
Ukraine had been begging for the long-range system because the missiles provide a critical ability to strike Russian targets that are farther away, allowing Ukrainian forces to stay safely out of range.
Information about the delivery was kept so quiet that lawmakers and others in recent days have been demanding that the US send the weapons – not knowing they were already in Ukraine.
For months, the US resisted sending Ukraine the long-range missiles out of concern that Kyiv could use them to hit deep into Russian territory, enraging Moscow and escalating the conflict.
That was a key reason the administration sent the mid-range version, with a range of about 100 miles, in October instead.
A senior US military official said on Wednesday that the White House and military planners looked carefully at the risks of providing long-range missile to Ukraine and determined that the time was right to provide them now.
Admiral Christopher Grady, vice chairman of the Joint Chiefs of Staff, told The Associated Press in an interview that long-range weapons will help Ukraine take out Russian logistics nodes and troop concentrations that are not on the front lines.
He declined to identify what specific weapons were being provided but said they will be “very disruptive if used properly, and I’m confident they will be”.
Ukrainian officials have not publicly acknowledged the receipt or use of long-range ATACMS.
But in thanking Congress for passing the new aid Bill on Tuesday, Ukrainian President Volodymyr Zelensky tweeted that “Ukraine’s long-range capabilities, artillery and air defence are extremely important tools for the quick restoration of a just peace”.
The US had refused to confirm that the long-range missiles were given to Ukraine until they were actually used on the battlefield and Kyiv leaders approved the public release.
One official said the weapons were used early last week to strike the airfield in Dzhankoi, a city in Crimea, a peninsula that Russia seized from Ukraine in 2014. They were used again overnight east of the occupied city of Berdyansk.
Videos on social media last week showed the explosions at the military airfield, but officials at the time would not confirm it was the ATACMS.