A suicide bomber has blown himself up at the ancient temple of Karnak in Luxor, a southern city frequented by millions of foreign and Egyptian tourists every year.

Officials say there is no immediate word on casualties from the late morning attack.

They say police have foiled two other suicide attacks also targeting the Nile-side temple, one of the country's main tourist attractions, rivalling the pyramids at Giza.

The attack was the first to target world-famous attractions in Luxor since November 1997, when Islamic militants opened fire on tourists at the city's 3,400-year-old Hatshepsut Temple on the west bank of the Nile, killing 58.

Tourism is the lifeblood of Luxor, home to some of Egypt's most famous ancient temples and pharaonic tombs, including that of King Tutankhamun.

The city has been hit hard by a downturn in foreign visitors during the years of unrest since Egypt's 2011 uprising.

There was no immediate claim of responsibility for Wednesday's attack, but it bore the hallmarks of Islamic militants who have been battling security forces in the strategic Sinai Peninsula for years.

Extremists in Sinai have targeted tourism sites to try to deny the government a key source of revenue.

Last year, the Sinai-based insurgent group Ansar Beit al-Maqdis pledged allegiance to the Islamic State group, which has destroyed famed archaeological sites in Syria and Iraq, viewing them as idolatrous.

The campaign of violence in Sinai accelerated and spread to other parts of Egypt following the 2013 military overthrow of Islamist president Mohammed Morsi.

The attack on the temple, which sits on the east bank of the Nile, comes as tourism was beginning to show signs of recovery after a four-year slump following the uprising that toppled longtime autocrat Hosni Mubarak.