About 150 British troops have joined Finnish and US forces for a "high-readiness exercise" in Finland.
The four-day exercise involved 750 troops from the three nations, the Ministry of Defence (MoD) said.
It comes just weeks after Nato signed an accession protocol with Finland to join the military alliance, beginning the process for membership.
Finland and Sweden, which have held neutral status for years, applied to join Nato after Russia invaded Ukraine.
The Kremlin has strongly opposed Finland and Sweden joining Nato and has issued threats over their plans to do so. Finland shares a 830-mile (1,340km) border with Russia.
British troops based in Estonia were flown to Finland in Royal Air Force Chinook helicopters as part of the exercise, according to the MoD.
The British personnel had been in Estonia as part of the British Arm's Project Unified Stance, which sees troops take on a series of exercises across Europe in coordination with Nato and allies.
Wing Commander Stephen Boyle, the UK defence attaché in Helsinki, said: "Our soldiers, sailors and aviators have received a warm welcome in Finland over the last few months.
"Exercise Vigilant Fox is the latest activity in an ongoing series of events across the domains.
"As Finland moves towards full Nato Membership, we will continue to seek opportunities like this to show solidarity with Finland, learn from each other and improve our ability to operate together."
Defence Minister James Heappey said the training, called Exercise Vigilant Fox, "demonstrated the strength and interoperability of our armed forces with our US and Finnish allies".
He added that it reaffirms the UK's commitment to the defence and security of the Baltic Sea region.
This latest exercise comes just days after the MoD revealed that six Royal Air Force fighter jets flew to Finland and Sweden for joint training exercises.
Source: BBC
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