July so far has been one of the deadliest months for coalition forces in southern Afghanistan, but military officials say that is because an increase in the number of U.S. troops has meant an increase in operations.

U.S. President Barack Obama has shifted his country's military focus from Iraq to Afghanistan, and the influx of U.S. troops is ushering in a "new phase" in the war, de Kruif said.

The NATO-led force in the south is expected to number some 45,000 troops by the time of the Afghan elections on Aug. 20.