This is the message from families of the eight South African aviation experts killed in yesterday's suicide bomb attack in the Afghanistan capital, Kabul.

Though details of the fatal blast are sketchy, it is believed the eight - two of whom were to have married their loved ones soon - stopped for fuel while travelling along the city's main road.

It was a stop the killer, a 20-year-old woman whose terror group was apparently enraged by the recent anti-Islamic US-made movie Innocence of Muslims was prepared for.

The bomb is believed to have been hidden in the Toyota Corolla that the woman drove into the men's minibus.

The blast completely destroyed the minibus, ripping the South Africans' bodies from the vehicle as it and several others burst into flames. In total, 12 people were killed.

The eight South Africans, who included pilots, engineers and aviation support staff, were working for aircraft chartering company BalmOral Central Contracts and the aviation sub-contracting firm CemAir.

CemAir leases aircraft to BalmOral, which has logistical chartering contracts with the allied forces and the Afghanistan government.

Mark van Buuren, the uncle of aircraft maintenance engineer Johan Bouchaud, 30 - who along with Fraser Carey, 31 - was killed in the blast, said: "None of us can believe it. It does not make any sense. There are no words to describe our pain.

"You see this on TV every day, but you don't expect it to happen to your family."

He described Bouchaud as an ordinary person "like you or me", who loved aircraft.

"Flying and aircraft were his life, his passion. This was not the first time [he went] to Afghanistan.

"Johan, who worked for CemAir, went to Afghanistan because he wanted to help his family. The money was good and he wanted to be able to support them," he said.

Van Buuren said Bouchaud was due to return to South Africa next week. "We were all looking forward to seeing him again. He had been gone for more than six weeks."

Van Buuren said all the family wanted was to get Bouchaud's remains home.

"That is the priority. All we want is our boy home, but it is not going to be easy. They still have to identify all of them before we can bury him."

Messages of support and love flooded the Facebook pages of some of the men.

"RIP chine, you will never be forgotten!! The way you took life in your stride and always put a smile on our faces," read one to Carey.

"Frankie my boy! Your shenanigans will never be forgotten neither your eternal thirst! Clear skies all the way my boy!"

Carey's former Johannesburg high school, King Edward VII, tweeted condolences to his family in a tribute to him.

BalmOral CEO Sej Dunning said Afghanistan had become chaotic following the anti-Islamic video, making it dangerous to travel from one side of Kabul to the other.

He said identifying the bodies was extremely difficult. "We are in the process of identifying bodies."

Many of the families of South African pilots and support staff working in Afghanistan waited in anguish yesterday for information about their loved ones.

Some received brief messages from men in Afghanistan informing them that they were okay. The men could not speak by phone because their communications are monitored by the US military.

A BalmOral staff member said the company provided aircraft, pilots, maintenance crew, administrators and "everything else their clients needed to run their own private flights". He declined to name its Afghanistan clients.

President Jacob Zuma sent condolences to the victim's families.

"I am deeply saddened by the deaths. Our thoughts and prayers are with the families of the deceased," he said.

The US embassy condemned the incident, with US ambassador Donald Gips saying: "This vicious attack again shows the insurgents have no respect for human life.

"As Secretary [of State Hillary] Clinton has said, there is never any justification for violent acts of this kind."

Nelson Kgwete, spokesman for the Department of International Relations and Cooperation, said it was offering consular support to the victims' families.

"The department is in contact with the aviation company that employed the deceased.

"The department is also in possession of the list of names of the deceased. Efforts to confirm their identities and to contact their next-of-kin are currently under way," he said.

"The department wishes to express its sincere condolences to the families, friends and colleagues of the deceased."