The US has approved the sale of 500 Patriot missiles to Ukraine, a critically-needed munition for defence against escalating Russian aerial attacks, after Kyiv said deliveries had been delayed in recent months.
The US State Department said the advanced PAC-3 interceptor missiles would cost $2.1bn (£1.6bn) and would be "funded entirely" by Kyiv's allies in Europe and Canada.
Ukrainian President Volodymyr Zelensky has repeatedly urged the US to speed up deliveries of its Patriots - the only effective weapon in downing Russia's deadly ballistic missiles.
The latest move comes just days after a row between Zelensky and Donald Trump, with the US president saying it was time for Ukraine to get a new leader to try to end the war with Russia.
In Friday's statement, the State Department said "this proposed sale will support the foreign policy and national security objectives of the United States by improving the security of a partner country that is a force for political and economic stability in Europe".
It said "Ukraine will pay for this purchase with donations from Canada, Germany, and Norway via the JUMPSTART program and national funds, financed by the European Union's Ukraine Support Loan".
The statement said the "principal contractor" would be American company Lockheed Martin, adding that "no US funds are involved in this sale".
Zelensky said earlier this week that his country had been waiting almost a month for the US to sign off on critical missile supplies.
And in a Telegram post late on Friday, the Ukrainian president reported that earlier in the day Russian ballistic missiles had struck two of the country's regions.
"They continue to carry out terrorist strikes against our cities," he said.
Zelensky has recently admitted that Ukraine was running critically low on Patriots, as Russia was intensifying its attacks on key energy infrastructure ahead of winter.
Kyiv desperately needs the interceptors but there is a global shortage of the munitions due to their use by the US in its war against Iran.
It is not clear what the production schedule will be for the Patriots - but it is understood the order is for new builds rather than existing missiles, meaning there is unlikely to be any kind of rapid delivery to Ukraine.
Patriots also have lengthy production times, with only 600 missiles produced per year according to the US Department of Defence.
In July, Trump said Washington had "not agreed" to license Ukraine to produce Patriots - three weeks after offering the country such a right.
