The attack took place in the Kajaki district of Helmand which is a Taliban stronghold.
Yousef Ahmadi, a Taliban spokesman confirmed the ambush had taken place, telling AFP their fighters had killed 25-30 "policemen" and that "two of our mujahideen were also martyred and four were wounded".
The Taliban controlled Musa Qala for most of 2007 and used it as a base from which to launch attacks. However, foreign forces wrested power from them at the end of last year during an operation that lasted several days.
However, Taliban fighters are still active in the region where they are believed to have the support of foreign sympathisers.
Salaam himself is a former Taliban commander who switched sides just before the military operation in 2007.
Previously, he was governor of the south-central Uruzgan province during the six years of Taliban rule in Afghanistan.
The Taliban was removed from power following the US-led invasion of Afghanistan in the wake of the September 11 attacks on New York and Washington.
Taliban leaders had refused to hand over al-Qaeda allies operating from Afghanistan.