A Northern Ireland-based army unit has taken command in Helmand in southern Afghanistan.
This is the first time 19 Light Brigade - which has about 3,000 troops normally stationed in NI, has provided the bulk of the UK force in Afghanistan.
The units are based at Lisburn, Ballykinler, Holywood and Antrim.
Brigadier Tim Radford said that they were "well prepared" for the challenges ahead.
"We are very well prepared for the myriad challenges that we face and through the provision of security, stability and reconstruction we will undermine the insurgents, help to expand governance and improve the day to day lives of the Afghan people," he said.
The flag of 19 Light Brigade replaced that of 3 Commando Brigade in the task force headquarters in Lashkar Gah.
The Commander of 3 Commando Brigade, Brigadier Gordon Messenger said they had "made a real difference to the security and wellbeing of southern Afghanistan".
"We will never forget those who have been killed or injured on our watch but as we reflect on the last six months the overriding feeling of 3 Commando Brigade is one of pride and satisfaction at a job well done," he said.
The UK currently has some 8,000 troops serving in the country, most of them in the southern province of Helmand.
Prime Minister Gordon Brown has offered to send more British troops to serve on operations in Afghanistan.
The troops would be sent to provide security ahead of the country's presidential elections in August.