A previously unknown Islamist group on Friday claimed responsibility for the Cairo bomb attack which killed three people and injured 19 others, according to an Internet statement.

The group calling itself the Islamic Brigades of Pride in the Land of the Nile said it carried out the suicide bomb attack that left a Frenchwoman, an American and another unidentified person dead on Thursday.

"We announce our complete responsibility for the blast in Cairo ... This martyrdom operation was carried out by Abu al-Alaa al-Masri," the statement said.

It said the location of the bombing was chosen because it was popular with tourists, adding it would soon issue a video of the attack.

The explosion took place at around 5:00 p.m. (1500 GMT) on Thursday in an open-air market close to al-Azhar mosque, one of the most revered shrines in the Sunni Muslim world.