Afghan President Hamid Karzai sent troops from the new national army to keep order in the western city of Herat on Monday after more than 100 people died in factional fighting following the killing of a minister.
Hundreds of troops, helmeted and armed with AK-47 assault rifles, machine guns and rocket launchers boarded transport planes supplied by US and British forces and took off from the capital Kabul in a major test for the newly established army.
A spokesman for powerful regional governor Ismail Khan, who regained control of the city on Monday and chased away a pro-Karzai commander in what appeared to be a struggle for power, initially said the troops were not needed.
But spokesman Ghulam Mohammad Masoan said later: "If this is what the government wants and it is for the expedience of the region, then we see no problem in it. Amir Sahib (Khan) sees no problem in it either."
On Sunday government commander and Karzai loyalist General Zahir Nayebzada was accused of killing Khan's son, Mirwais Sadiq, who was also the aviation minister in Karzai's cabinet.
Khan's spokesman blamed the killing on personal rivalry, but Nayebzada said he had acted in self-defence and accused Khan of trying to take over his division in a struggle for control of the normally peaceful city.
More than 100 people, including civilians, were reported to have been killed in ensuing clashes, some of the worst violence between pro-government factions since Karzai was installed in power after US-led forces ousted the Taleban in 2001.