Almost half the country is controlled by the Taliban right now.
There are fears Russia may be helping fund the fundamentalist group.
An American solider died and a helicopter was downed as fierce fighting raged between the Taliban and Afghan government forces, but details of the incident remain sparse.
The Taliban is fighting hard to take Helmand, the center of Afghanistan's opium industry, and the national army is able to stop the advance only with help from Western armed forces.
Afghan forces are desperately trying to retain control of Sangin, a district capital in Helmand province, which is on the verge of falling back into Taliban hands.