Nearly three hours after the attack began, gunfire was still being heard as police special forces tried to end the siege. Mr. Khogyani said four attackers were involved, though a security official put the number at three. The official said that two of the attackers had been killed, and that they believed one was still resisting in the British aid agency’s offices.
Officials said that the Jalalabad office of Save the Children, which works on health and education issues, shares a wall with another aid organization, Swedish Committee for Afghanistan, and that the Swedish group’s staff had been evacuated.
The Islamic State’s local affiliate in Afghanistan claimed responsibility for the attack, according to the group’s Amaq news agency. Save the Children’s main Afghanistan office said it was “devastated.”
“This is an outrage,” Nicholas Kay, the British ambassador to Afghanistan, said on Twitter. “Any attack on children & humanitarians is a crime against humanity. I hope for a quick and safe end to this horrific incident in Jalalabad.”
The pace of violence across Afghanistan has been relentless in recent weeks, with civilians bearing the brunt. On Saturday, the Taliban attacked a packed hotel in Kabul, killing at least 22 people and terrorizing much of the Afghan capital for nearly 15 hours of fighting.
Aid organizations have been targeted repeatedly in recent years, forcing some of them to cut back their operations. The Red Cross recently closed its offices in two northern provinces and scaled back operations in a third regional hub after repeated attacks targeting its staff. In the latest episode, one of its physiotherapists was shot dead as she was assisting a polio patient.