At least 50 people have died in fighting in western Afghanistan between forces loyal to Herat governor Ismail Khan and a rival militia.
Factional fighting flared between rebel commander Amanullah Khan's forces and Governor Khan's men on Saturday.
The heaviest clashes were centred on an air base north of Shindand. It remains unclear who has control of the base.
President Hamid Karzai condemned the fighting as an attempt to disrupt presidential elections in October.
He has vowed to take serious measures against the rebels.
The Afghan defence ministry says it will intervene to defend Ismail Khan against his rivals, the BBC's Andrew North reports from Kabul.
Shindand is about 660km (412 miles) west of the capital Kabul. There was also fighting between the rival factions to the north of Herat city and in Chisti.
Amanullah said his men, armed with machine guns and rockets, had killed 14 of Governor Khan's troops and captured 20.
Seven rebels had also died in the fighting, which began at 0200 (2100 GMT on Friday) in Shindand district, he told the Associated Press news agency.
Karzai condemned the violence
Mr Khan, known as the "emir of Herat", has in the past been seen as one of the main obstacles to President Karzai's efforts to extend his authority outside Kabul.
He controls one of the country's largest private militias.