CAIRO — Militants opened fire on a van filled with plainclothes police in a Cairo suburb early Sunday, killing eight of them, including an officer, in an attack claimed by a local Islamic State affiliate.

The attack was the deadliest in the heavily policed capital since November, when gunmen attacked a security checkpoint, killing four police officers. That attack was also claimed by the local ISIS affiliate.

Egypt’s state-run MENA news agency said the officers were inspecting security in the south Cairo suburb of Helwan early Sunday when four gunmen in a pickup opened fire on them.

Interior Minister Magdy Abdel-Ghaffar, in charge of police, ordered an investigation into the attack.

An Islamic State affiliate claimed responsibility for the attack in an online statement, saying it killed everyone in the vehicle. It said the operation was to avenge women jailed in Egypt. The claim could not be independently verified, but the statement’s language and the nature of the attack suggest it is authentic.

Associated Press