CAIRO — ISIS’s Egypt affiliate said it was behind a car bombing that wounded 30 people, including eight policemen, near a state security building and courthouse in a Cairo suburb on Thursday.

A statement circulated on Twitter by supporters of the group, Sinai Province, said the bomb was a reprisal for the execution of six of its members convicted of carrying out an attack north of the Egyptian capital last year.

“Let the apostates of the police and army, the followers of Jews, know we are a people who do not forget our revenge,” the statement said.

In May, Egypt executed six members of Sinai Province for attacking soldiers near Cairo in 2014. The men were convicted on charges that included carrying out an attack in Arab Sharkas village, north of Cairo, in which two army officers were killed.

Sinai Province has killed hundreds of soldiers and police since the military toppled President Mohamed Morsi of the Muslim Brotherhood in 2013.

Comments on Twitter indicated the blast, which heavily damaged the face of the state security building, was heard in several parts of the Egyptian capital.

Shopkeeper Mohamed Ali said he saw a man park a vehicle that exploded after he stepped away from it.

Egyptian President Abdel Fattah al-Sisi has vowed to eradicate militancy, which he has said is an existential threat to the Arab world and the West.

This month Sisi approved an anti-terrorism law that sets up special courts in response to the two-year-long Islamist insurgency that aims to topple his government.

The law has come under fire from human rights groups that accuse Sisi of rolling back freedoms won in the 2011 uprising.