The explosion struck near the historic Khan el-Khalili market in eastern Cairo, where tourists shop for trinkets and sit at outdoor coffee shops. Egyptian Health Minister Hatem el-Gabali said a French woman was killed.
Blood-stained entrance to mosque after attack (Photo: AP)
The minister said 25 people were wounded, including 10 French tourists, one German and three from Saudi Arabia. The sources said six people had been seriously wounded.
At least one device exploded after being thrown from a motorcycle and bomb disposal experts were trying to defuse a second device which was also thrown, the sources added.
It was not clear who was behind the attack or if the tourists had been deliberately targeted, although Islamic terrorists have hit the country's tourist industry in recent decades through bomb and shooting attacks.
Tourism in Egypt, the most populous Arab country, reached record levels last year after a lull in deadly attacks over the last few years.
But in September last year, masked gunmen seized 19 hostages, including 11 tourists, on a safari in a remote desert area near the Sudanese and Libyan border. All were released unharmed.