British troops on Thursday began the opening stages of an assault in what is shaping up to be the latest large-scale attack on the Taliban.

The Ministry of Defense confirmed a softening-up operation is under way to clear insurgents from their stronghold just west of Lashkar Gah, the capital of Helmand province in Afghanistan.

It is potentially the biggest offensive since Operation Panther's Claw which cost the lives of 10 U.K. servicemen last summer.

It follows Friday's seizure by insurgents of a building in the city from where they were able to fire towards the governor's compound.

Code-named Operation Mostarak -- Pashtun for "Together" -- the ongoing offensive will include 2,700 of Kabul's soldiers.

That is the largest commitment of local forces to a combined attack so far. It has been described as the "high water mark" of Afghan involvement.

The British military's chief spokesman on Afghanistan, Maj. Gen. Gordon Messenger said that in the last 36 hours troops from the Grenadier Guards, the Scots Guards and the Royal Welsh had attacked from helicopters and on foot.

There were no reports of U.K. casualties.

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