Some 200 people are now reported to have been arrested in the Afghan city of Herat since the killing of the minister for civil aviation there.
Afghan soldiers have been sent to Herat, but are not on the streets
They include a man who says he was responsible for Mirwais Sadeq's death, a senior member of the Herat provincial government told the BBC.
Mr Sadeq was the son of the governor of Herat, Ismail Khan, one of Afghanistan's most powerful figures.
The central government has been deploying soldiers to the area.
Soon after Sunday's killing, fighting broke out between rival factions.
The BBC's Crispin Thorold says the city is now calm.
The government has been sending more members of the Afghan National Army (ANA) to Herat, but they have not yet started patrols within the city.
As the official mourning period for Mirwais Sadeq continues in Herat, regional and national leaders are meeting to try to resolve the political fall-out from the minister's death.
Our correspondent says it is not clear how Ismail Khan will react to the efforts of the central government to deploy the army.
Mr Khan has until now enjoyed a great deal of autonomy in the west of Afghanistan.
Deputy Defence Minister General Rahim Wardak has warned that Kabul would ask Ismail Khan to give up his weapons.
He has said that the ANA is the only legitimate force in the country, and no-one would be allowed to have personal armies.
Meanwhile sources in Herat say that at least 13 people died in fighting which broke out after the killing of Mr Sadeq on Sunday between troops loyal to Ismail Khan and a senior local military commander, Zahir Nayebzada.
Earlier reports said that around 100 people died in the clashes.
Mr Khan proclaimed his son a martyr at his burial in Herat on Wednesday, and demanded that the government find his killers.
He blames his son's death on forces belonging to Mr Nayebzada, who have now fled the city.