The number of Mexican tourists accidentally killed by Egyptian security in the western desert on Monday has risen to eight, security and judicial sources said.

The tourist group of 22 had parked their four four-by-four vehicles off road for a barbecue near the Bahariya oasis, a tourist site in the western desert, when army aircraft began shelling them, security sources said.

Authorities originally said at least two Mexicans had died. Initial reports had put the total number of deaths at 12 including two Mexicans and Egyptians.

A joint force from the Egyptian police and military was chasing militants in the country's vast western desert, which borders Libya, when it inadvertently opened fire on the convoy, the earlier reports said.

Mexican President Enrique Pena Nieto condemned the attack on his Twitter account, describing it as a tragic incident and demanding a full investigation.

"Mexico condemns these deeds against our citizens and has demanded an exhaustive investigation of what has occurred," he tweeted.

Egypt's tourism ministry spokesman told state news agency Mena the convoy was at an off-limits site and was using unlicensed cars. The convoy was taking part in an unapproved safari, he said.

Mexican ambassador Jorge Alvarez met with five Mexicans who were in stable condition in hospital, Mexico's foreign ministry said.

Egypt is battling an insurgency that gained pace after the military ousted Islamist President Mohamed Mursi of the Muslim Brotherhood in mid-2013 after mass protests against his rule.

The insurgency, mounted by Islamic State's Egyptian affiliate, has killed hundreds of soldiers and police and has started to attack Western targets.

Earlier on Sunday Islamic State released a statement carried by its supporters on Twitter saying it had repelled an attack by the Egyptian military in the western desert.

While the insurgency has been largely based in the Sinai Peninsula, attacks have taken place in Cairo and other cities. In August, an Egyptian military aircraft crashed in the western desert near the Libyan border while on a mission against Islamist militants, killing four people.

Security officials say militants operating from Libya to the west of Egypt have been trying to forge ties with Islamists in the Sinai on the east side of the country.

Egyptian jets bombed Islamic State targets in Libya in February, a day after the group there released a video showing the beheading of 21 Egyptian Christians, drawing Cairo directly into factional conflict across its border. - Reuters