CAIRO (Reuters) - Egyptian Army aircraft hunting for militants in the desert mistakenly bombed a convoy of mostly Mexican tourists, killing 12 people and wounding 10, authorities said on Monday.

Survivors said their group was bombed from a plane and helicopters. As members of the tourist convoy tried to flee, additional forces on the ground fired on them, Egyptian security sources said.

Egypt’s interior ministry described the attack in the country’s western desert as an accident.

Mexico’s President Enrique Pena Nieto said two Mexicans were killed in Sunday’s incident, though Egyptian security and judicial sources later said eight Mexicans and four Egyptians were killed. The sources said eight Mexicans and two Egyptians were wounded.

In Mexico, the sister of a Reiki healer who said her brother was among the dead, said a relative of the group’s tour guide had sent her a list of eight Mexicans killed in the attack.

The group of 22 had parked their four 4x4 vehicles off-road on Sunday for a barbecue near the Bahariya oasis, a tourist site in the western desert, when army aircraft suddenly began shelling them from above, security sources said.

“Unfortunately we have confirmed that two (Mexicans) lost their lives and six more were wounded,” Pena Nieto said, condemning the incident. “Mexico has demanded the Egyptian government conducts a swift, exhaustive investigation.”

Mexico’s ambassador to Egypt, Jorge Alvarez, said six Mexicans who survived the incident were in stable condition. Alvarez added that the government was still seeking information about six other Mexicans of the 14-strong group still unaccounted for.

Alvarez identified the two dead as Luis Barajas Fernandez and Maria de Lourdes Fernandez Rubio.

In Washington, U.S. State Department spokesman John Kirby said an American might be among those injured in the attack.

“We’ve seen reports that potentially a U.S. citizen was injured,” Kirby told a daily briefing. “Our embassy in Cairo is making the appropriate inquiries with local police, and of course, they’re monitoring it.”

Pena Nieto said he had been assured Egypt’s prime minister would personally spearhead a probe.

Alvarez said the survivors he visited in hospital had told him they had been bombed by helicopters and an aircraft while they stopped for a break in the desert. The tourists had arrived in Egypt on Sept. 11.

Reuters spoke to Araceli Rangel Davalos, whose nephew Rafael Bejarano, a Reiki healer and musician was killed. She said her sister Marisela was wounded. She said she knew the group’s guide, an Egyptology expert whom she identified as Nabil Altawami, well. She had not yet spoken to her sister.

“I have traveled with the guide around 9 times, and he never exposed us to any danger,” she told Reuters by telephone. “He protected us.”

Gabriela Bejarano, Rafael’s sister, cast doubt on the Egyptian government’s account of the incident.

“I don’t think they were mistaken (for militants),” she told local radio in Mexico. “As far as I understand ... they were dining when they came under attack ... They were in a permitted area. On this occasion they didn’t stay to camp, because that was what was not permitted.”

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Egypt’s ambassador to Mexico, Yasser Shaban, said he assured Mexico’s government Egypt was taking the incident very seriously and was committed to establishing exactly what happened.

ISLAMIST INSURGENCY

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.

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A joint force from the Egyptian police and military had been chasing militants in the country’s vast western desert when it came across the tourist convoy, which it mistook for the militants it was pursuing, the Interior Ministry said in a statement.

An Egyptian army representative declined to comment.

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.

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.

The vehicles used by the tourist convoy closely resembled those of the militants the joint force had been pursuing, security sources said.

‘RESTRICTED AREA’

Egyptian tourism federation chairman Elhamy Elzayat told Reuters: “The area is a restricted area, and the company made a mistake by taking the tourists to that area without a permit. They must obtain a permit before going there.”

Officials at the company that organized the tour were not immediately available for comment.

There are no warning signs along the desert path, despite the apparent danger of the area and the attack occurred despite an official police representative accompanying the tourist convoy, said tour guide syndicate leader Hassan al-Nahla.

“Because of this negligence and lack of coordination between the ministry of tourism and ministry of interior, Egypt...will pay the price when this affects tourism,” said al-Nahla.

While the Islamist insurgency has been largely based in the Sinai Peninsula, attacks have taken place in Cairo and other cities.