In pictures: UK and US offensives in Afghanistan

Troops from Britain, the US and Afghanistan are fighting a large-scale offensive to drive Taliban insurgents from Helmand Province. Soldiers from the Welsh Guards are seen firing into suspected enemy positions.

US marines are taking part in Operation Khanjar which aims to take, and hold, Afghan territory in advance of next year's elections.

UK troops launched their offensive - Operation Panther's Claw - with a similar objective of gaining and holding territory. Here, Guards have fixed bayonets before they storm an enemy position.

The 4,000 US marines taking part in the Operation Khanjar offensive say they have met fierce resistance from some insurgents.

UK troops carry a wounded soldier to a waiting Blackhawk Medevac helicopter after a prolonged contact with Taliban insurgents.

The US marines dispatched by President Obama to Afghanistan represent a "surge" that the US hopes will drive the Taliban out for good.

The war in Afghanistan began in 2001 with the NATO-led, UN authorized response to the September 11 attacks. The stated aim of the invasion was to find Osama bin Laden and other al-Qaeda members and put them on trial.

The UK's Defence Secretary Bob Ainsworth said there was "no end date" in sight but that "for Britain to be secure, Afghanistan needs to be made secure". His comments came as a seventh UK soldier died in a week.