Five people died and 24 were injured after a suicide car bomb was detonated and gunmen stormed the building and compound in Jalalabad on Wednesday.
The claim of responsibility was made via the extremists’ media channel Amaq, although no evidence was presented to back up the group’s assertion.
The attack began at 9.10am local time at the government building in the eastern Nangarhar province. Unconfirmed reports said at least four of the attackers were wearing police uniforms – a tactic commonly used by extremists.
Residents fled the area as Afghan special forces arrived on the scene. Around 10 hours later, the last attacker of around six still holding out against the security forces was killed.
“There was a blast and the target was Save the Children,” local government spokesperson Attaullah Khogyani said in a statement.
Around 50 people are believed to work in the government building; for the British charity, a Swedish aid group and the Afghan Department of Women’s Affairs.
It is believed 45 people sheltered in a safe room inside the compound during the siege.
Two of the dead were guards at the compound, and one was a civilian. It was not immediately clear if the other two dead were attackers or civilians.
Pictures from the scene showed a huge plume of black smoke rising into the air, burnt-out vehicles and dozens of soldiers on the perimeter of the compound.
“An explosion rocked the area and right after that children and people started running away,” eyewitness Ghulam Nabi told Reuters. “I saw a vehicle catch fire and then a gunfight started.”
The violence follows a Taliban siege over the weekend of Kabul’s Intercontinental Hotel in which 22 people were killed.
Afghanistan has been engulfed by a rising wave of violence across the country since international troops withdrew in 2014.
Since then, the Taliban has managed to seize control of around 40 per cent of the country – although it holds no cities – and other militant organisations such as Isis have gained a firm foothold.
The security forces, civilians and foreigners, including aid workers, are frequently targeted in extremist attacks.
Wednesday’s events have forced the children’s charity – which says it helps 1.4 million minors in the country – to temporarily close all of its Afghan offices and programmes.
“We are devastated at the news that our Save the Children office in Jalalabad city, Afghanistan, came under attack this morning,” a Save the Children spokesperson in London said in a statement.
“Our primary concern is for the safety and security of our staff.
“We remain committed to resuming our operations and lifesaving work as quickly as possible, as soon as we can be assured that it is safe to do so.”
Last year the Red Cross also announced a drastic scale back of operations in Afghanistan after seven of its staff were killed by extremist violence.
Join our new commenting forum
Join thought-provoking conversations, follow other Independent readers and see their replies