Egypt's Interior Ministry says the multiple-car crash on a Cairo street in front of the country's main cancer hospital that killed at least 20 people involved a car bomb.
Monday's statement by the ministry says an Islamic militant group, known as Hasm, with links with the outlawed Muslim Brotherhood group, was driving the car with the bomb late on Sunday down the Corniche, intending to carry out a militant attack elsewhere in the country when the crash set off the bomb and the explosion took place.
President Abdel-Fattah el-Sissi called the explosion a "terrorist attack."