Egyptian forces hunting militants in the country’s western desert mistakenly opened fire on several vehicles used by Mexican tourists, killing 12 people on Sunday.

Mexicos Foreign Relations Department said Tuesday that embassy personnel in Egypt have identified six more bodies as those of Mexican citizens killed in air attack by Egyptian police and military forces.

The deaths of two Mexicans had earlier been confirmed, bringing the total number of Mexicans killed to eight.

Six other Mexicans were injured in the attack. The department said Tuesday their condition is stable. There were 14 or 15 Mexicans who traveling on a desert oasis tour at the time.

Egyptian forces hunting militants in the country’s western desert mistakenly opened fire on several vehicles used by Mexican tourists, killing 12 people on Sunday.

The other dead are believed to be Egyptians.

Foreign Relations Secretary Claudia Ruiz Massieu called the aerial attack “an unjustified aggression.”

The sister of one of the Mexican tourists killed said her brother, Luis Barajas Fernandez, 49, had been visiting Egypt for the first time.

“He had never gone to Egypt before,” said Ana Barajas, who lives in the northern Mexico state of Tamaulipas. “It was for pleasure,” she said of the trip.

The married 49-year-old had worked as a salesman in hospital and medical supplies.

“It is an unparalleled hurt,” she said of his death, adding the Mexican government was going to take care of the response to her brother’s death, and the repatriation of his remains.

Egyptian officials said the group did not have permission to be in the area, but have not offered a full account of Sunday’s incident, in which a total of 10 people were wounded.

Two other Mexican dead have been identified by name as Maria de Lourdes Fernandez Rubio and Rafael Bejarano.

The incident, among the deadliest involving tourists in Egypt, comes as the country is trying to revive its vital tourism industry after the turmoil following the 2011 uprising that toppled President Hosni Mubarak.

Egypt has mainly been battling insurgents in the northern Sinai Peninsula, on the other side of the country, where Islamic militants stepped up attacks on security forces after the military ousted Islamist President Mohammed Morsi in 2013 amid massive protests against his rule.

But in recent months, militants loyal to the Islamic State of Iraq and Syria (ISIS) have carried out a series of attacks in more central parts of the country, including the bombing of the Italian Consulate in Cairo and the kidnapping and beheading of a Croatian oil surveyor who was working in the capital.

Egyptian officials claimed the safari convoy had wandered into a restricted area. The tour company involved “did not have permits and did not inform authorities,” Rasha Azazi, a spokeswoman for the Egyptian Ministry of Tourism, told The Associated Press, adding that any trips to that area must be cleared by officials. “They were not supposed to be there,” she said, without providing further information about the incident.

Egypt’s western desert has long been a popular safari destination, with tourists flocking to its verdant oases, unique rock formations and white sand dunes.

In recent years, however, it has been the subject of security concerns because of the long, porous border with Libya. Egypt has been flooded with weapons, mostly from Libya, since the 2011 uprising that toppled longtime Libyan dictator Moammar Gadhafi and plunged that country into turmoil.

Egyptian security forces frequently target smugglers in the western desert, and in July 2014, gunmen armed with rocket-propelled grenades attacked a border guard post, killing 21 troops.