CAIRO, May 8 (Aswat Masriya) – Two militant groups, including the Islamic State's affiliate in Egypt, claimed responsibility for an attack that killed eight policemen in the early hours of Sunday in Helwan in Greater Cairo.

According to a statement by the interior ministry, four unidentified assailants with automatic weapons stopped a police vehicle carrying eight policemen dressed in civilian clothes. The policemen were inspecting the security situation in a Helwan district.

In a statement that circulated on social media networks, the Islamic State's affiliate in Egypt claimed responsibility for the attack and said that it comes as part of a series of attacks “in retaliation” for women's imprisonment in Egyptian jails.

Another group known as the “Popular Resistance” also claimed the attack on Sunday via social media networks.

The group, however, said that it dedicated this operation to those killed during the dispersal of the Rabaa al-Adawiya protest camp in August 2013 as the attack comes on the occasion of the passing of 1,000 days since Rabaa's dispersal.

Aswat Masriya could not independently verify the authenticity of both statements.

The sit-in at Rabaa Al-Adawiya was staged in support of former Islamist president Mohamed Mursi, who was ousted by the military in July 2013 following mass protests against his rule. It was one of two large sit-ins which were violently dispersed by security forces leaving at least 1,000 people dead in what Human Rights Watch described as "likely amounted to crimes against humanity."

The Egyptian state's Forensic Authority, however, claimed that 627 were killed in the dispersal, while the National Council for Human Rights put the death toll at 632, including eight security personnel. 

Today's attack on policemen was condemned by the U.S. embassy in Cairo and the European Union delegation in Egypt.

Similar attacks have taken place across Egypt since the ouster of Mursi. The group affiliated to the Islamic State claimed responsibility for a number of operations targeting vital facilities and security personnel. Most attacks occurred in North Sinai at first; but they have later crawled into other parts of the country, including the capital.