Operation Moshtarak, a joint offensive by more than 15,000 American, British and Afghan soldiers on the Afghan city of Marjah, is entering its fifth day.

The pace of fighting has slowed with pockets of Taliban offering fierce, but unco-ordinated resistance.

The greatest challenge facing international forces at the moment seems to come from the improvised explosive devices left by Taliban fighters.

Despite their progress, US commanders on the ground say Operation Moshtarak could take up to one month.

It is all part the American strategy to "clear, hold and build". But US forces have 'cleared' areas before only to have the Taliban return once they pull back.