Two foreigners are among four people to have been killed in an explosion in the Egyptian capital Cairo. At least 14 others were wounded, six of them seriously.Police say one of the foreigners killed was a French national. Reports suggest other French citizens and German tourists are among the injured. The blast tore through an area popular with holiday-makers – the Khan-el-Khali market, in the east of the city. Witnesses have been quoted as saying a bomb exploded after being thrown from a motorcycle. Some international news agencies say security forces discovered discovered another unexploded device nearby. It was not clear who was behind the apparent attack or if tourists had been deliberately targeted. Islamic militants have previously attacked foreign visitors to the country.