After a violent campaign directed at security forces, Egyptian militants appear to be zooming in on President Abdel Fattah al-Sisi's most vulnerable point: the economy.

Attacks on two prime tourist sites in the space of eight days are deeply worrying for a government that has staked much of its credibility on reviving the economy after years of political turmoil.

A suicide bomber blew himself up on Wednesday near the ancient Karnak temple in Luxor, wounding four Egyptians. A week earlier, two police officers were killed in an attack near the Giza Pyramids, hundreds of miles to the north.