A suicide bomber has killed 33 people queuing outside a bank in Jalalabad in what is thought to be the first terrorist attack in Afghanistan carried out by Islamic State.
Government employees were targeted in Saturday's attack - the worst in Afghanistan since November - which was thought to have been carried out by a suicide bomber on a bicycle or motorbike. Another blast took place near a shrine and municipality buildings, and bomb disposal experts detonated a third explosive device.
Smoke billowed from the building and windows were shattered in the blast, which left people lying in pools of blood and body parts scattered across the ground. Dr Najeebullah Kamawal, head of the provincial hospital, said that over 100 people were injured in the bomb – among them many children.
Taliban spokesman Zabihullah Mujahid said that his group was not behind the "evil" attack.
Ashraf Ghani, the president of Afghanistan, condemned the attack and said Islamic State of Iraq and the Levant (Isil) had claimed responsibility.
"Carrying out terrorist attacks in cities and public places are the most cowardly acts of terror by terrorists targeting innocent civilians," he said, on a visit to northeastern Badakhshan province.
"Who claimed responsibility for the horrific attack? The Taliban did not claim responsibility for the attack, Daesh (Isil) claimed responsibility for the attack."
Last month Mr Ghani had used a visit to the White House to announce that Isil had already sent "advance guards" to his country, and warn of impending attacks.
An Isil spokesperson, Shahidullah Shahid, claimed responsibility online, and identified the suicide bomber as Abu Muhammed Khurasani. Shahid is among a number of former Taliban leaders and groups that have declared their allegiance to Abu Bakr-al Baghdadi, the self-styled Caliph of Isil, which has overrun parts of Syria and Iraq.
Isil published an image of Khurasani, kneeling before an Isil banner and with a Kalashnikov beside him, reading what looked like a suicide note.
An email from the group reportedly confirmed the claim, and boasted of "sending 75 government servants to hell."
And the explosion would mark the first time that Isil have carried out a terrorist assault inside Afghanistan.
In September the group published leaflets claiming that Pakistan and Afghanistan formed part of their territory. A Taliban fighter in Afghanistan told the BBC at the time that many of his organisation were considering throwing their support behind Isil.
"We are waiting to see if they meet the requirements for an Islamic caliphate," said Commander Mirwais. "We are sure that our leadership will announce their allegiance to them. They are great mujahideen."
A month later the Pakistani Taliban, under the command of Shadid, announced that they were supporting Isil. The Taliban have now seen a series of defections to Isil in recent months, with some insurgents voicing their disaffection with their one-eyed supreme leader Mullah Omar, who has not been seen since the 2001 US-led invasion of Afghanistan.
Saturday's attack now means that Isil are active in Libya, Egypt and Afghanistan – as well as the territory they control in Syria and Iraq.
Nigeria's Islamists, Boko Haram, announced their allegiance to Isil in March – but most analysts dismissed that as empty posturing. Isil are thought to be courting Somali terrorists with Al Shabaab, but no formal link has been declared.
And the bombing came as Afghanistan braces for what is expected to be a bloody push by the Taliban at the start of the fighting season. The Taliban have stepped up attacks on government and foreign targets since Washington back-pedalled on plans to shrink the US force in Afghanistan this year by nearly half.