The first of 1,000 additional UK troops to be sent to the lawless Helmand province in Afghanistan have arrived in the country.
The troops stopped in Kabul en route to Helmand province
More than 3,000 British troops have been deployed to Afghanistan since May. The current deployment will boost numbers to 4,500.
They are there to combat the resurgent Taleban, the drug trade, and help reconstruction efforts.
It comes after six UK soldiers were killed in Helmand in the past month.
The 1,000 troops are primarily made up of infantry and engineers and are part of a strengthened Nato force.
Released photographs show the first wave of troops - from the Second Battalion, The Royal Regiment of Fusiliers - arriving in the Afghan capital Kabul, en route to Helmand province.
"These troops will enable our commanders to secure our presence and that of the Afghan government in northern Helmand," said a spokesman for the International Security Assistance Force.
"We are there to prevent Afghanistan from again harbouring terrorism, to build security and government institutions so that the progress of recent years becomes irreversible.
In total, 4,500 UK troops will now be in Afghanistan
"And to combat the narcotics trade, the residual Taleban insurgency and illegally armed groups, all of which remain threats to Afghan security and stability."
In a Commons statement on Monday, Defence Secretary Des Browne said 320 engineers from 28 Regiment Royal Engineers would be used to "accelerate the reconstruction effort" in Afghanistan.
A company from 3 Commando Brigade Royal Marines would provide force protection for them and those deployments would take place from September. More helicopters would also be provided.
An extra infantry company, taken from the 2nd Battalion The Royal Regiment of Fusiliers, would also provide more mobile forces.
And two platoons from the 1st Battalion, The Royal Irish Regiment would provide additional force protection.
The defence secretary said there would also be a "small increase" in HQ staff and medical and logistical support.
In total, 450 reservists were being called up to fill 400 posts "in theatre".
Mr Browne told MPs some extra troops would be going immediately, others in October.