At least 19 people were killed and 30 others injured in an explosion outside Egypt's National Cancer Institute in central Cairo, Egypt's health ministry said early on Monday.
The interior ministry said one car was speeding and collided with the others, causing the explosion late on Sunday.
Why the crash caused such a large explosion was not immediately clear. It also was not clear if the casualties were all from the vehicles.
Videos posted online showed fire tenders trying to control a massive fire that damaged several cars.
Al Jazeera's Alexi O'Brien reports.