Prime Minister Rishi Sunak says he is "pleased that UK-donated kit will be keeping the Ukrainian armed forces warm and safe as they face a perilous winter fighting for their country".
The UK is sending heated tents and extreme cold weather sleeping kits to Ukraine to help the country's armed forces cope with plummeting temperatures there. Commando T Shirt Army
A further 12,000 kits are being provided to the country's armed forces, along with 150 of the tents.
The kits contain a cold weather sleeping bag, bivvy bag and roll mat.
Defence Secretary Ben Wallace said the items were being made available in addition to "lethal aid".
The UK is also on course to deliver 25,000 sets of extreme cold weather clothing by mid-December, Downing Street said.
They include an insulated jacket, trousers and extra-warm boots, gloves and socks.
They are on top of more than 7,000 sets of normal cold weather kit distributed to recruits on Operation Interflex, Number 10 added.
Operation Interflex is the name given to the training of Ukrainian troops pioneered by the UK.
Mr Wallace said the equipment would help the Ukrainians to "operate effectively through the next few months".
He added: "Alongside our training programme and the provision of lethal aid, it demonstrates our commitment to making sure that the basic Ukrainian soldier is well trained, well equipped and given the best possible chance to fight and determine their own future."
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The announcement coincides with a visit from NATO Secretary General Jens Stoltenberg to Downing Street on Wednesday - the first international leader Prime Minister Rishi Sunak has hosted at Number 10 since taking office last month.
Before arriving in Westminster, Mr Stoltenberg will visit Ukrainian troops at Lydd Army Camp in Kent.
He will watch as recruits are put through their paces by UK military trainers, preparing them for active service on the front line in Ukraine.
Once across the table from the prime minister, Mr Stoltenberg and the PM will discuss both the ongoing war in Ukraine and how best Kyiv can be supported.
There will also be some discussion of the Integrated Review - an assessment of the UK's national security policies.
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Regarding the UK's relationship with the military alliance, Downing Street said: "The UK is the largest European contributor to NATO, and has committed both our aircraft carrier and our nuclear capability to the alliance."
Speaking ahead of Mr Stoltenberg's visit, Rishi Sunak said: "NATO is the cornerstone of our security, and the security of our allies. As the war in Ukraine continues to rage, we must not take peace at home for granted.
"I am determined the UK will be the bedrock of NATO for generations to come. But in order to face the challenges of the future we must evolve as an alliance to meet, and remain ahead of, the threat from our adversaries.
"We must also continue backing the Ukrainian people in their resistance to Putin's brutality.
Military Army T Shirt "I'm pleased that UK-donated kit will be keeping the Ukrainian armed forces warm and safe as they face a perilous winter fighting for their country."