Cairo: Two Egyptian policemen and a civilian were wounded in a bomb attack targeting a security checkpoint in central Cairo on Tuesday, officials and a medic said.

The device, which was placed between two cars near the checkpoint at Al Galaa Square in Dokki neighbourhood, exploded at about 7.15 am local time, a security official said.

Previously, security officials said that assailants threw a homemade bomb at the checkpoint. Egypt has been rocked by a series of bombings and shootings carried out by militants since the military ousted Islamist president Mohammad Mursi in July.

The military-installed authorities say militants have killed about 500 people since the overthrow of Mursi. Most militant attacks have been in the restive Sinai Peninsula, but in recent months brazen attacks have also been launched farther afield in the Nile Delta and in the capital Cairo.