A multinational force commanded and led by British troops has launched a major offensive against the Taleban in the southern Afghan province of Helmand.
By Jill McGivering
BBC News, Helmand
The operation involves about 700 men, mostly infantry and engineers.
This is the biggest operation in the province since June and a key part of a wider plan to push the Taleban north.
Violence has soared in Afghanistan and more than 3,000 people have been killed this year as Afghan and foreign forces battle Taleban fighters.
The operation started at the crack of dawn as tanks and infantry rolled through the desert to enter a fertile green belt, a Taleban stronghold.
It would allow international forces to secure the main supply routes running between the larger towns.
In the last six months there have been steady military gains but at a cost.
At least 27 British soldiers have been killed and there is little sign of any reduction in the violence.
International troops and Afghan security forces face ambushes, rocket attacks and bombs on a regular basis.
Civilians in the towns now controlled by the troops increasingly face a new threat from suicide bombers.