The journalists were filming a documentary about anti-poaching activities in the Western African nation with a well-known ranger when their convoy was ambushed.

Two Spanish journalists making a documentary about anti-poaching efforts and an Irish ranger were kidnapped and killed in Burkina Faso, according to the Spanish government and a wildlife conservation organization, following recent warnings by the authorities about a possible resurgence of attacks in the West African nation.

The killings on Monday came as violence is increasing in Burkina Faso and the security situation in the Sahel is deteriorating, especially in the border area of Burkina Faso, Mali and Niger. Burkina Faso has seen attacks from many armed groups, several of them linked to the Islamic State and Al Qaeda in the Islamic Maghreb.

Attackers on motorbikes have stormed countless villages, forcing residents to convert to Islam and sometimes killing them even when they do. Others have ambushed military patrols and killed members of the armed forces, and hundreds of schools have been forced to close because of the violence.

On Tuesday, Prime Minister Pedro Sánchez of Spain confirmed the deaths of the two Spanish journalists, whom he identified on Twitter as David Beriain and Roberto Fraile.

The conservation organization Chengeta Wildlife said its co-founder and chief executive, Rory Young, was the third victim. Mr. Beriain and Mr. Fraile were following Mr. Young, a Zambia-born Irish national, for their documentary, Chengeta Wildlife said on Facebook.

Movistar+, the Spanish television platform for which Mr. Beriain was filming the documentary, confirmed that Mr. Young was the third victim.

The two journalists were part of a group of 40 who were ambushed on Monday in a nature reserve in eastern Burkina Faso near the border with Benin, said Arancha González Laya, Spain’s foreign minister.

The authorities in Burkina Faso said in a statement on Tuesday evening that the country had faced “a resurgence of terrorist acts” since Sunday, and that around 10 people had been killed in several attacks.

Six people were injured in the ambush on the convoy on Monday, and a Burkinabe soldier was still missing on Tuesday evening. The fate of the others in the convoy, and the identities of those who carried out the killings, remained unclear.

The eastern parts of Burkina Faso, particularly around the city of Fada-Ngourma near the reserve where the journalists were abducted, have been a perilous area because of the armed groups operating there over the past few years.

Last year was the deadliest for militant Islamist violence in the region, according to the Africa Center for Strategic Studies, a U.S. Defense Department research institution. About 4,250 people were killed — a 60 percent increase over 2019 — with the Islamic State in the Greater Sahara linked to more than half of the deaths.

On Tuesday, the United Nations said a record 29 million people were in need of humanitarian assistance and protection in six countries of the region, among them Burkina Faso and Chad, where the killing of the president, Idriss Déby, last week could further destabilize the region.

Mr. Déby, who had a poor human rights record, was a key figure in regional efforts to fight off Islamist insurgents in alliance with French and African forces. About 1,200 Chadian troops were deployed this year in the border area between Burkina Faso, Mali and Niger, where Al Qaeda in the Islamic Maghreb has made significant strides.

In Burkina Faso, violence has fueled a fast-growing displacement crisis, with more than a million people fleeing their homes since 2019, according to the United Nations’ humanitarian affairs body. Three million people are in need of humanitarian assistance, in a country with a population of 20 million.

In addition to violence from militants, Burkina Faso’s military has killed growing numbers of civilians, sometimes in proportions similar to those killed by Islamic insurgents, according to rights groups and analysts.

In July, the bodies of at least 180 men thought to have been killed by security forces in the preceding eight months were found in the country, according to witness testimonies collected by human rights researchers.

The two Spanish journalists had histories of working in conflict zones.

Mr. Beriain, 43, had reported from Afghanistan, Congo, Iraq and Libya, among other places, according to the regional Spanish newspaper La Voz de Galicia, for which he worked for six years. He also directed a documentary about the nuclear disaster in Fukushima, Japan, and the film he was working on about Burkina Faso was scheduled to air on Movistar, a Spanish television channel.

Mr. Fraile, 47, also covered several conflicts and was injured in 2012 while covering the civil war in Syria.

Mr. Young was a well-respected guide and ranger who had worked in several African countries, and whose organization provides a mix of traditional training to detect poaching groups, and crime scene investigation skills. Mr. Young had said that his organization was training 900 rangers and other personnel last year to track poaching and wildlife trafficking activities.

In his last Instagram post on Friday, Mr. Young said learning to track animals was like learning to read.

“It opens up a whole world of knowledge,” he wrote.

The ambush, in the reserve of Pama, part of the Arli National Park, occurred near Pendjari National Park, where a guide from Benin and two French tourists were abducted in 2019. The guide, Fiacre Gbédji, was killed, and the two Frenchmen were later rescued, although two French soldiers were killed in a raid to liberate them.

Several other foreigners have also been taken hostage in recent years.

In 2016, an Australian couple were kidnapped in the north of the country on the day that armed fighters killed dozens of people in the capital, Ouagadougou.

In 2018, a Canadian woman and an Italian man were abducted in the country They were released 15 months later in neighboring Mali. And in 2019, a Spanish Catholic missionary was killed.

In 2017, Mr. Young of Chengeta Wildlife told The New York Times that the organization’s anti-poaching activities were only possible if it managed to build constructive relationships with the local populations to stay updated on events in the region.

“Without the community there is no solution,” Mr. Young said.

Yet Mr. Young also often acknowledged the risks of the rangers’ mission. In July, he wrote on Instagram about training local rangers.

“We do that with them on the frontline,” he wrote.