Six Afghan policemen have been killed in an ambush by suspected Taleban and al-Qaeda fighters, provincial officials say.
A spokesman for the governor of Helmand Province said the men died when their vehicle was attacked with rocket-propelled grenades and automatic rifles.
The policemen were ambushed late on Sunday.
News of the attack came soon after a senior official in another southern province appealed for help from US-led coalition forces.
The deputy governor of Zabol Province called on the coalition to mount a military operation against resurgent Taleban forces in the area.
The province's own forces were unable to cope, said Mullah Mohammed Omar, who shares his name with the ousted Taleban leader.
Hundreds of Taleban fighters were roaming freely in several districts, he said, intimidating government employees and supporters.
Zabol is the only province in Afghanistan where the Taleban have named their own governor and officials to rival those appointed by the government in Kabul.
International forces are being asked to intensify operations
In April this year the Taleban captured a district in the north of Zabol, Deh i-Chopan, before government troops were sent to retake control.
Afghan government troops have been deployed in the southern province of Paktia in the first major combat operation for the Afghan National Army (ANA).
About 1,000 ANA soldiers - a fifth of its total trained manpower - were deployed on Tuesday along with US and Italian troops in an operation aimed at tracking down Taleban and al-Qaeda fighters.
A US spokesman for Operation Warrior Sweep reported uncovering arms dumps along the border with Pakistan.
However, Colonel Rodney Davis said on Friday, there had been no "contact" with militants.