Afghan security forces blocked roads and took up positions around the house of vice president Rashid Dostum on Tuesday as a standoff flared up over accusations his men tortured one of his political opponents.
In an address to supporters at his Kabul residence, broadcast live on television, Dostum warned President Ashraf Ghani that any action against him would weaken the government but said he would not order his own militia fighters to take action against government forces.
"My message to the president is to maintain our national unity," he said.
Dostum, an ethnic Uzbek warlord who has manoeuvred his way through decades of Afghan conflict, faces accusations that he ordered members of his militia forces to detain Ahmad Ishchi, a former ally, who says he was severely beaten and threatened with sexual violence over several days.
Foreign governments, including the United States, have expressed serious concerns over the case and last month, the attorney general's office issued arrest warrants against nine of Dostum's bodyguards.
The men have not so far been taken into custody, however, and the standoff has increased widespread perceptions of the fragility of Ghani's national unity government, formed after the disputed election of 2014.
Dostum's chief of staff Babur Farhamand said it was not clear why security forces had been stationed around the vice president's heavily fortified residence but their presence was causing concern.
"The security forces who are taken position near the compound of first vice president are not giving us a clear answer about their presence," he told Afghanistan's One TV.
"They tell us that they are here to ensure the security of the first vice president but this heavy military presence has raised the anger and concern of the vice president's supporters," he said.
As night fell, police appeared to have withdrawn from the area but the sight of armed forces in the streets heightened the sense of growing tensions within the government.
The Ishchi case has caused severe embarrassment to Ghani, who brought Dostum into the government despite accusations of serious human rights violations by his forces.
Since then, he has been a difficult and unpredictable ally and has repeatedly clashed with Ghani but his standing among the Uzbek minority, estimated to make up around 9 per cent of the population, has made it hard to replace him in the government.
Western officials have said they want to see the case tried in court to show that high officials cannot break the law with impunity but the tangled realities of Afghan politics and the fragility of Ghani's government have so far delayed any action.