Public anger has mounted after an explosives-laden sewage tanker detonated in Kabul's diplomatic quarter on Wednesday, killing 90 people and wounding hundreds of others in the deadliest attack in the Afghan capital since 2001.
Hundreds of demonstrators calling for President Ashraf Ghani to step down and chanting "Death to the Taliban" clashed with police near the bombing site, prompting officials to beat them back with live rounds, mostly in the air, tear gas and water cannon.
"In today's protest four people died and eight others were wounded," health ministry spokesman Waheed Majrooh told AFP. Local media reported the death toll was as high as seven.
Kabul has been on edge since the bombing, which highlighted the ability of militants to strike even in the capital's most secure district, home to the presidential palace and foreign embassies that are enveloped in a maze of concrete blast walls.
Friday's killings will likely further inflame passions, as angry protesters marched through the streets carrying bloodied corpses of those killed in the clashes but they were stopped from reaching the presidential palace.
Residents of the city have demanded answers from the government over the perceived intelligence failure leading to the assault, which underscores spiralling insecurity in Afghanistan.
"Our brothers and sisters were martyred in the bloody attack on Wednesday, and our leaders are doing nothing to stop this carnage," Rahila Jafari, a civil society activist, said during the protest.
"We want justice, we want the perpetrators of the attack to be hanged to death."
Other enraged protesters, carrying banners with gruesome images from the bombing, burned effigies of the president and demanded that his government resign.
"It is absolutely shameful that government forces used live rounds and tear gas against grieving protesters who are demanding justice for victims of the bombing," Afghan MP Fawzia Koofi told AFP.
Taliban threaten hostages
Afghanistan's intelligence agency has blamed the Taliban-allied Haqqani Network for the attack.
Ghani is expected to approve the execution of 11 Taliban and Haqqani prisoners, a government source told AFP, in apparent retaliation to the assault.
The Taliban -- currently in the midst of their annual "spring offensive" -- denied they were involved.
The insurgents have threatened "harsh exemplary attacks" in a statement on their website, including the killing of foreign hostages they hold if the government carried out the executions.
Following their threat, the American University of Afghanistan appealed to the Taliban to release two professors, American Kevin King and Australian Timothy Weeks, who were abducted in August last year.
The two appeared in a Taliban hostage video in January, the first proof that they were alive.
The Taliban also hold Canadian Joshua Boyle and his American wife Caitlan Coleman, who had two sons in captivity after being kidnapped in Afghanistan in 2012 during a backpacking trip.
The Haqqani Network, long thought to have ties to neighbouring Pakistan's shadowy military establishment, is led by Sirajuddin Haqqani -- who is also the Taliban's deputy leader. It has carried out numerous attacks in Kabul, including the 2008 Indian embassy bombing that killed almost 60 people.
With more than 400 wounded in Wednesday's bombing, the injured have crowded into hospital hallways as people were still searching for missing relatives.
Health officials have warned that some victims may never be identified as their bodies were torn into pieces or burned beyond recognition.