At least 95 people were killed and 191 wounded in the lunchtime attack claimed by the Taliban, which caused panic in the war-torn capital and overwhelmed its hospitals.
US President Donald Trump called for "decisive action" against the Taliban over the assault -- the second it has carried out in the city in a week -- as other international leaders also condemned the attack.
"We have 95 dead and 191 wounded from yesterday's attack in Kabul," health ministry spokesman Waheed Majroh told reporters on Sunday.
Most of the injured were men, he added.
Ordinary Afghans took to social media to express their anguish and sorrow at rapidly worsening security, as the Taliban and the ISIS group step up attacks on Kabul, turning it into one of the deadliest places in Afghanistan for civilians.
"We are so heartbroken in Kabul that we don't know how to start our new day," Freshta Karim wrote on Twitter.
"Shall we stay home or go to work, shall we meet our friends and cry or shall we force ourselves to create an illusion of hope? How are you starting your day in Kabul?"
Naser Danesh tweeted: "In Kabul starting a day without explosion, it would be a surprise. One could only imagine that kind of a day."
On Facebook, Naweed Qaderi wrote: "It is a big shame for the government, they repeatedly fail to protect people. The leaders must lose a son or daughter to feel the pain of poor people."
The blast happened in a crowded area of the city where several high-profile organisations including the European Union have offices.
The force of the explosion shook the windows of buildings hundreds of metres away and caused some low-rise structures in the immediate vicinity to collapse.
The government has blamed the Taliban-affiliated Haqqani Network, which Afghan and Western officials suspect of involvement in at least some of the recent attacks in the capital.
The suicide bomber passed through at least one checkpoint in the ambulance, saying he was taking a patient to Jamhuriat hospital, an interior ministry spokesman told AFP on Saturday.
"At the second checkpoint he was recognised and blew (up) his explosive-laden car," Nasrat Rahimi said.
Rahimi told a news conference later that most of the victims were civilians. Four suspects had been arrested.
The attack came exactly a week after Taliban insurgents stormed Kabul's landmark Intercontinental hotel and killed at least 25 people, the majority foreigners.
But there is still confusion over the true toll with conflicting figures given by officials and Afghan media reporting higher numbers.
A security alert issued on Sunday warned that ISIS militants were planning to attack supermarkets and shops in Kabul frequented by foreigners.
Some foreign organisations are reassessing their presence in Afghanistan following the spate of deadly violence, with at least one moving its foreign staff out of Kabul, a Western source told AFP.
(This story has not been edited by NDTV staff and is auto-generated from a syndicated feed.)