UPDATE: Kabul bomb attack, death toll keeps rising

Kabul residents are mourning the loss of family members, friends and colleagues, a day after a massive truck bomb in the Afghan capital killed at least 90 people and wounded more than 450 others in one of the worst attacks in recent years.

Scores of people waited in hospitals on Thursday to learn the status of loved ones wounded in an attack that killed mostly civilians, including women and children, but also Afghan security guards.

A suspected suicide bomber drove into Kabul's heavily guarded diplomatic quarter during the morning rush, leaving behind chaos and destruction.

READ: 8 killed, 25 wounded in Kabul suicide bomb attack

The sound of the bomb, which went off near Kabul's busy Zanbaq Square, reverberated across the city, with residents comparing it to an earthquake.

Mohammad Ismail Kawusi, health ministry spokesman, said that the identification process of victims had resumed on Thursday.

However, "some bodies will probably never be found, they were torn to pieces", he said, adding that some of them were hardly identifiable.

"For God's sake, what is happening to this country?," said Ghulam Sakhi, a shoemaker whose shop is close to the site of the blast.

"People leave home to fetch a loaf of bread for their children and later that evening, their dead body is sent back to the family," Sakhi said.

There was no claim of responsibility for Wednesday's attack, though Afghanistan's spy agency blamed the Taliban-allied Haqqani network and neighbouring Pakistan for the blast.

Angry citizens demanded answers from the government over the perceived intelligence failure leading to the attack, which underscores spiralling insecurity in the country.

"For how long will we have to tolerate this bloodshed in our country?" a sobbing resident asked during a local news interview.

"I have lost my brother in the blast and the government is constantly failing to provide us with security."

The explosives were hidden in a tanker truck used to clean out septic systems, according to Najib Danish, deputy spokesman for the interior minister.

The trucks are common in Kabul, a city of nearly four million people with no sewage system that mostly depends on septic tanks, and where open sewers are common.

The blast gouged a crater of about five metres deep in an area close to many foreign embassies, which are protected by their own security personnel as well as Afghan police and National Security Forces. The nearby German Embassy was heavily damaged.

Also in the area is Afghanistan's foreign ministry, the presidential palace and its intelligence and security headquarters, guarded by soldiers trained by the US and its coalition partners.

Afghan President Ashraf Ghani condemned the bombing, the deadliest single attack in Kabul since the Taliban were toppled from power in a 2001 US-led invasion, as a "war crime".

Afghanistan's war, the longest ever involving US troops, has shown no sign of letting up and the introduction into the battle of an Islamic State of Iraq and the Levant (ISIL, also known as ISIS) affiliate has made the country only more volatile.