The death toll from a powerful suicide attack claimed by the Taliban in Kabul has risen to at least 103 people, the interior ministry said on Sunday.

Kabul residents are grieving and the government has declared a day of mourning after the suicide bomb attack on Saturday in the city centre, which also wounded 191 people.

Kabul was on high alert, with security beefed up particularly near the blast scene - an area close to an interior ministry building, the Jamhuriat hospital, government offices, businesses and a school.

The assault, carried out by a bomber driving an explosives-laden ambulance, was the worst attack in the Afghan capital since May 31, 2017, in which at least 150 people were killed. No group claimed responsibility for that blast.

Residents told Al Jazeera they fear more attacks in the coming days, as they feel the government has failed them.

"We are tired of people being killed in huge numbers in a matter of seconds. I don't think the Afghan government can ever protect us. It is a normal thing for them now. We should be careful and take care of ourselves," said Nadir, a Kabul resident.

Nadir, who witnessed Saturday's attack, said women and children were among the dead.

"Most of them killed were civilians, our hearts are crying for the innocent people who got killed. Everyone is sad here," he told Al Jazeera.

He was among those who helped the injured.

"Some lost their legs, others arms, some had their faces destroyed. It was blood everywhere. The images keep flashing in front of me," he said.

Rising attacks

The Taliban claimed responsibility for Saturday's assault, the third major attack in the past seven days, saying its target was government officials.

A Taliban-claimed attack on the Inter-Continental Hotel in the city, which left more than 20 dead, was carried out a week earlier. On January 24, the Islamic State of Iraq and the Levant (ISIL, also known as ISIS) killed at least three people at the office of Save the Children in Jalalabad.

Saturday's attacker was able to race through a security checkpoint by saying he was transferring a patient to a hospital.

Huge plumes of dark smoke rose over the city and vibrations could be felt several kilometres away.

For hours, Ramin Afshar searched for his friend, Nasir Ataee, who had recently started working at the interior ministry.

"He was missing until this morning," Afshar told Al Jazeera. "We found him in the military hospital. Besides being burned, he also lost a leg."

Al Jazeera's Jennifer Glasse, reporting from Kabul, said Afghan officials were calling the attack a "massacre".

"In the immediate aftermath of the attack, we saw bodies scattered across the street," she said. "The hospitals are inundated with the wounded and officials fear the death toll may rise."

Ahmed Naweed, a witness, told Al Jazeera: "There were many dead bodies and blood everywhere," he said. "People were crying and screaming and running away."

Kabul residents took to social media to express their anger and sorrow at the worsening security situation as the Taliban and ISIL step up attacks.

Matiullah Wesa, an education activist in Afghanistan, wrote: "This is our life in #Afghanistan everyday looking for loved ones to be safe from danger. Calling friends and family to find out how they are. This is our daily routine because of the enemies of Afghanistan."

A picture of a father crying over the loss of his son has gone viral.

A man breaks down after hearing his son was killed during today's attack in #Kabul everyday life in capital #Kabul #Afghanistan.

Photo:omer Subhani pic.twitter.com/nsb1yO1w9l — Hbabur (@Humayoonbabur) January 27, 2018

Commenting on Saturday's bomb blast, Dejan Panic, coordinator at a hospital run by the Emergency NGO, said: "It's a massacre."

Abdullah Fahimi, a Kabul-based researcher, told Al Jazeera that the attack could be in response to the government's recent efforts to pound the Taliban in remote areas, in addition to recent US sanctions on its members.

Fahimi explained: "This is an impasse, neither side is winning. The [Taliban] group is not going to surrender or give up; they want to take more areas, territories."

On Friday, the administration of US President Donald Trump sanctioned four Taliban and two Haqqani network leaders "who have been involved in attacks on coalition troops, smuggling of individuals, or financing these terrorist groups", said Sigal Mandelker, undersecretary for terrorism and financial intelligence, a position within the US treasury department.

With reporting by Al Jazeera's Shereena Qazi: @ShereenaQazi