Cairo last week announced a major operation against jihadists across swathes of territory, including the volatile region which has been at the heart of a persistent Islamic State group insurgency.

The security sweep in the Sinai, Nile Delta and Western Desert near the border with Libya comes as the country prepares for polls next month in which President Abdel Fattah al-Sisi is seeking re-election.

Army spokesman Tamer el-Refai said at a press conference broadcast Thursday that intelligence showed that jihadists were planning "to create a new terrorist home base in another area that could potentially be the Sinai Peninsula".

The spokesman told a tightly controlled press conference that 53 jihadists have been killed since the start of the operation, while more than 600 people have been detained.

There was no way to independently verify the figures given.

In November, Sisi ordered his armed forces chief of staff to restore security in Sinai within three months after militants killed more than 300 worshippers at a mosque.

Egypt has been under a state of emergency since April last year, after two suicide bombings at churches claimed by IS killed at least 45 people in the cities of Tanta and Alexandria.