French special forces freed four hostages in Burkina Faso late last week in a raid that left two of the elite soldiers dead.

Cedric de Pierrepont and Alain Bertoncello were killed in the nighttime raid to free two French citizens, Laurent Lassimouillas and Patrick Picque. During the operation, two additional hostages not identified by initial intelligence reports were discovered in the enemy encampment; these hostages, an American woman and a South Korean woman, were also freed.

French authorities said the hostage-takers were terrorists who kidnapped Lassimouillas and Picque, two French tourists, on May 1. The two music teachers were on a safari in Benin’s Pendjiari National Park, an area French authorities have warned citizens against visiting. Their guide, Fiacre Gbédji, was murdered in the kidnapping.

According to the BBC, the kidnappers were on their way to Mali. It is believed they planned to hand over the hostages to the militant group Katiba Macina.

“Once the hostages were in [Katiba Macina’s] hands it would have been impossible to rescue them,” Francois Lecointre, France’s army chief, said in a news conference.

Four of the kidnappers were killed during the rescue and two were reported to have escaped. Although no group has taken responsibility for the kidnapping, authorities said groups tied to al-Qaeda and the Islamic State both operate in the region.

Armed Forces Minister Florence Parly said the two women had been held captive for 28 days, and that despite the special forces troops having US intelligence support for the operation, that neither the US nor South Korea were aware their citizens had been taken.

“The contacts [with those countries] show that the countries were not necessarily aware of their presence,” Parly said.

Both women will be returned to their home countries.

A spokeswoman for the US State Department told Reuters that the US was grateful for the rescue and also offered official condolences to the families of the fallen soldiers.

In a press conference after meeting Macron in France Saturday, Lassimouillas also extended his condolences to the families of the fallen troops, as well as to the family of his safari guide. He also said that he was sorry he failed to heed the government’s travel warning and that he wished he had “avoided that magnificent region of the world that has unhappily tipped into instability.”

French President Emmanuel Macron met with the hostages as they arrived in France Saturday, and honored the soldiers who died on Friday.

“They gave their lives to liberate others,” Macron said on Twitter Friday of de Pierrepont and Bertoncello. Macron announced a formal memorial service for the two men will be held Tuesday in Paris.

Bertoncello’s parents, Jean-Luc and Daniéle Bertoncello, said he’d wanted to join the navy since high school and that they were proud of him.

“What he loved was the esprit de corps ... he was doing what he wanted and he always told us not to worry,” they said in an interview with RTL radio. “They did what they had to do. For him it ended badly, for the others, it was a successful mission.”