Britain is sending helicopters to Ukraine, Defence Secretary Ben Wallace has said, the first piloted aircraft to be sent by the UK since the war began.
Three former British military Sea Kings will be provided and the first has already arrived, the BBC understands.
In the last six weeks, Ukrainian crews were trained in the UK to fly and maintain the aircraft – to provide search and rescue capabilities.
Mr Wallace said the UK would also send an additional 10,000 artillery rounds.
He made the announcement from Oslo, where he is meeting allies to discuss ongoing military support for Kyiv.
The defence secretary said the artillery rounds would help the Ukrainian armed forces secure recently-liberated territory.
The Sea King was previously used by both the Royal Air Force and the Royal Navy, with the last craft being retired by the Navy in 2018.
Few countries have sent manned aircraft to Ukraine since the start of the conflict, and requests by its government for Western nations to send fighter jets so far remain unanswered.
At the weekend, Prime Minister Rishi Sunak used a visit to Kyiv to set out a new £50m package of defence aid which included 125 anti-aircraft guns and equipment to counter Iranian-supplied drones.
That followed an announcement earlier this month that an additional 1,000 surface-to-air missiles would be sent.
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The UK is also supplying Ukrainian troops with winter equipment, including heavy duty sleeping bags and mats, as well as heated accommodation and cold-weather clothing.
Temperatures during winter can fall as low as -20C in parts of Ukraine.
Britain remains the second largest donor of military aid to Ukraine after the United States, and speaking from Oslo Mr Wallace said its support would remain “unwavering”.
The trip to Oslo will see Mr Wallace host a meeting of the Northern Group – a UK-led initiative to bolster defence cooperation between the countries of northern Europe – on board HMS Queen Elizabeth.
Defence ministers from across the region are expected to discuss the implications of Russia’s invasion of Ukraine, Sweden and Finland’s applications for Nato membership, and the broader security picture for northern Europe.