The Black Watch started its first deployment to Afghanistan in April
British soldiers have launched a major airborne assault on a Taliban stronghold in southern Afghanistan.
More than 350 troops from the Black Watch were dropped into Babaji, north of Lashkar Gah, Helmand province, just after midnight local time on Friday.
Twelve Chinook helicopters were used in Operation Panther's Claw which involved British and US air forces.
The Ministry of Defence has described it as one of the largest air operations in modern times.
Lt Col Nick Richardson, spokesman for Task Force Helmand, said: "The aim is to secure a number of canal and river crossings in an area which has previously been one of the main Taliban strongholds.
"We are working very closely alongside the Americans and together we are seeking to reduce the fear, intimidation and violence that the insurgents cause and inflict on the Afghan population."
Black Watch soldiers remain in the area to construct permanent checkpoints with bulletproof barriers, for use by the Afghan National Police, but will withdraw in the coming days, the MoD says.
BBC News defence correspondent Caroline Wyatt says the arrival of extra US troops in the south of Helmand province has helped make such an operation possible.
It has allowed British forces to focus on taking on the Taliban in their strongholds, and keep the ground they have won.
Apache and Black Hawk helicopter gunships, as well as a Spectre gunship, Harrier jets and unmanned drones, supported the operation.
It was backed by more than 150 ground troops from the Black Watch and Royal Engineers using Viking armoured vehicles.
The aim was to establish a permanent presence in the area ahead of the Afghan presidential elections in August.
"The MoD says the Black Watch fought off several attacks by insurgents, and secured three main crossing points," said our correspondent.
These were the Lui Mandey Wadi crossing, the Nahr-e-Burgha canal and the Shamalan canal.
They found and disabled several of one of the Taliban's main weapons - improvised explosive devices - which have proved deadly to coalition forces over recent months, along with several landmines.
In addition, they uncovered a stockpile of 1.3 tonnes of poppy seed. Opium production funds much of the Taliban's activity in the area.
The operation comes after the 169th British serviceman was killed in Afghanistan since 2001 on Friday.
The Black Watch, 3rd Battalion, The Royal Regiment of Scotland (3 SCOTS), based at Fort George barracks near Inverness, started its first deployment to Afghanistan in April.