British troops in Afghanistan undertook their biggest operation since the fall of the Taleban in 2001 on Saturday.
British forces were backed by US and Canadian troops
Three hundred soldiers - backed by hundreds of American and Canadian troops - took control of Sangin in the southern province of Helmand.
Six British troops have been killed in or near the town in recent weeks.
Military chiefs earlier defended their decision to call in US planes to drop 500lb bombs on Taleban fighters in the nearby town of Nawzad.
Afghan president Hamid Karzai has ordered an investigation into the circumstances surrounding the Sangin fighting, which has left 10 Taleban dead.
Apache attack helicopters led the way early on Saturday for Chinooks which dropped the British troops on the ground - much of the fighting force of 3 Para battle group.
They were backed up by a further 700 coalition troops, including Afghan and Estonian forces.
They sealed off the town and targeted a number of compounds which are being searched.
Captain Drew Gibson, spokesman for British forces in Helmand, said the situation was "all quiet" as night fell, but the large contingent remained in the area.
A Ministry of Defence spokeswoman said the operation was part of an ongoing 'cordon and search' operation. Hundreds of Taleban fighters are said to have massed in the area to carry out attacks in recent months.
"The purpose of it is to disrupt Taleban activities which in recent weeks have included attacks on both Afghan security forces and coalition forces in this area," she said.
"During this operation suspected Taleban opened fire on UK helicopters from at least one location with at least four RPGs and in response to this a single missile and 30 rounds of a 30mm cannon were returned.
"When the firing point was later secured, two dead Taleban were found. Four Afghan women were also found in the vicinity, one of whom had been slightly hurt."
Three soldiers suffered minor injuries, and were all expected to make full recoveries. Capt Gibson said only one of them was hurt as a direct result of enemy action.
Coalition spokesman Major Scott Lundy said the British troops had killed 10 Taleban and driven the others out.
"But it is difficult to say if the remainder are still nearby," he said.
Alastair Leithead, the BBC's correspondent in Afghanistan, said the UK military was trying to secure the "hearts and minds" of the local population by bringing security to the area and bringing "development behind it".
Earlier military chiefs denied killing civilians when US planes, called in by UK troops, dropped 500lb bombs on Taleban fighters in Nawzad.
Witnesses said there were many killed and injured, and a school was among the buildings hit, but UK forces said there was no evidence of this.
Skirmishes have taken place across the south of the country over the weekend, killing at least 26 suspected Taleban militants.
The fighting is part of Operation Mountain Thrust, which was launched in mid-May.
But the Afghan Independent Human Rights Commission has said there has been a worrying increase in the number of civilian casualties there.