Four injured trying to defuse bomb near luxury Cairo hotel

Two policemen and two hotel guards were wounded as they tried to deactivate the explosive device found outside Le Meridien at Giza, he said. 

The blast, near one of Egypt's most visible tourist attractions, left one of the policemen in critical condition.

In June a gunmen shot and killed two police officers, a few hundred yards from the pyramids. Tourism is a vital source of foreign currency for the government. It has been hit hard by political turbulence in the country in recent years, although the government earlier this year said that the sector had begun rebounding. In September, however, security forces accidentally killed eight Mexican tourists and their guides in a botched operation. 

Elsewhere in Egypt, four policemen were wounded in the North Sinai town of El Arish in an explosion as they drove past in an armoured vehicle.

On Thursday, Egypt's armed forces said that they had gained full control over the North Sinai areas of El Arish, Rafah and Sheikh Zuwaid after successful raids on terrorist strongholds and weapons caches.

Egypt has killed 20 fighters in North Sinai, wounded 12 and arrested 78 more in joint police and army raids, the Egyptian army spokesperson said, while adding that Egyptian forces dismantled 51 explosive devices and destroyed motorcycles used by militants.

North Sinai is a bastion of the Egyptian affiliate of the Islamic State (IS) group.

The insurgency has swelled since the army's removal of Egypt's first democratically elected president, Mohamed Morsi, in July 2013.

Despite repeated attempts by the military to root out the militants, hundreds of Egyptian soldiers and policemen have been killed, largely in the Sinai. 

Since Morsi's overthrow, more than 1,150 people have been killed, some 40,000 arrested and hundreds more, including Morsi, sentenced to death in highly controversial mass trials.