Afghanistan's biggest suicide bomb attack is now known to have killed 59 schoolboys, the Education Ministry said on Friday, announcing a nationwide ban on students greeting politicians or dignitaries.
Five teachers and six members of parliament were also killed in Tuesday's blast in the relatively peaceful north of Afghanistan which has shaken public faith in the ability of the government and foreign troops in the country to provide security.
The suicide bomber blew himself up as schoolboys lined up to greet a visiting delegation of opposition parliamentary deputies in the town of Baghlan.
"We have 64 martyrs, 59 of them are children, and five of them are teachers," said Education Ministry spokesman Zahoor Afghan. "There are 96 wounded. Of those three are teachers, the rest are students."
Officials had previously put the total death toll at 52. As well as the boys, teachers and parliamentarians, a number of police and adult civilians were also killed in the attack. No schoolgirls were among the dead, Afghan said.
"The minister has repeatedly requested school children not to be sent to any welcoming ceremony, unless it is purely for educational programmes," said spokesman Afghan. "We told the provincial educational heads not to involve children in any programme other than educational, but they did not listen to us.
"But this time the education minister has issued a firm order and has strongly emphasised not to ever use any school children in any gathering or ceremonies after the incident in Baghlan."
A number of the wounded children were in critical condition with internal bleeding. Some might well die.
"It is quite possible the number of martyrs will increase because as of yesterday the death toll was 63, but one schoolboy succumbed to his injuries and died," Afghan said, adding that the region lacked medicine and proper health care facilities.
Some families had taken away the bodies of their relatives straight after the attack and it may be some time before a final death toll is known.
It was also too early to say who might have been responsible for the blast, officials said.
Afghan police detained two men on suspicion of involvement, the governor of Baghlan province said on Friday.
Taliban insurgents have carried out more than 130 suicide attacks in Afghanistan this year, but denied they carried out the Baghlan attack. The denial has sparked widespread speculation and conspiracy theories over who might be responsible amid a general atmosphere of fear and suspicion.
One of the two men arrested in Baghlan was a mosque prayer leader, the other a resident of the town's industrial zone where the blast took place, provincial governor Mohammad Alam Ishaaqzai told Reuters .
"The initial investigation shows these men may have had a hand in this attack," he said, but declined to say whether the men were affiliated to any insurgent or political group.
A high-ranking Interior Ministry team from Kabul were questioning the pair, he said.
Northern Afghanistan has been relatively peaceful and prosperous compared with the south and east, where Taliban suicide attacks are common and insurgents are locked in daily battles with Afghan and foreign forces.