It’s the latest attack on security forces in a region where tensions have long simmered between locals and the state.

In a statement on X on Saturday, President Gabriel Boric called the attack in Arauco province’s Canete municipality “cowardly” and declared three days of national mourning to honour the officers, identified as Sergeant Carlos Cisterna, Corporal Sergio Arevalo and Corporal Misael Vidal.

“Today the entire country is in mourning. There is heartbreak, sorrow, anger. But these emotions do not paralyse us, they force us, they mobilise us,” Boric wrote. “We will find the whereabouts of the perpetrators of this terrible crime.”

Authorities said the officers responded to three false emergency calls and were attacked in their vehicle with heavy-calibre weapons. They burned inside the armoured patrol vehicle on a road near the city of Concepcion, some 400km (about 250 miles) south of the capital, Santiago.

It remains unclear who carried out the assault but a long-simmering conflict between the Mapuche Indigenous community and landowners and forestry companies in the region has intensified in recent years. The conflict forced the government to impose a state of emergency and deploy the military to provide security.

In Chile, about one in 10 citizens identify as Mapuche, the tribe that resisted Spanish conquest centuries ago and was defeated only in the late 1800s after Chile won its independence.

Large forestry companies and farm owners control large tracts of land originally belonging to the Mapuche, many of whom now live in rural poverty.

Boric, who travelled to the area on Saturday with a large contingent, including top military and congressional officials and the president of the Supreme Court, offered condolences to the victims’ families, promising the killers would be found and brought to justice.

“There will be no impunity,” he said after firefighters dousing the burning police car made the grisly discovery.

In Santiago, hundreds of people gathered outside the presidential palace to protest against the killings, which coincided with National Police Day, celebrating the 97th anniversary of the establishment of the Carabineros, Chile’s military police force. It was the second such fatal attack on the force this month.

Ricardo Yanez, the Carabineros’s general director, told reporters the officers had been dispatched in response to fake distress calls from the rural road, where they were met with a barrage of gunfire.

“This was not coincidental, it was not random,” he said of the ambush.

The spate of bloodshed has tested Boric, who came to power in 2022 promising to ease tensions in the region, where armed Mapuche activists have been stealing timber and attacking forestry companies that they claim invaded their ancestral lands.

Boric’s administration has touted its success in reducing Chile’s national homicide rate by 6 percent, according to government figures from 2023 published earlier this week.

“This attack goes against all the enormous strides that have been made,” said Interior Minister Carolina Toha, a centre-left former mayor of Santiago.