A new report says that children as young as 11 were beheaded by militants in Mozambique’s troubled Cabo Delgado province, where a local Islamist insurgency is battling against the government forces.

Save the Children, an aid group based in Britain, said in a short account released Tuesday that it had spoken to displaced families who gave details of their young children being killed by militants from the local group referred to as al-Shabab.

“That night our village was attacked and houses were burned,” a woman referred to as Elsa, 28, told the organization. “When it all started, I was at home with my four children. We tried to escape to the woods, but they took my eldest son and beheaded him.

“We couldn’t do anything because we would be killed too,” Elsa said. Her son was 12, according to Save the Children.

A 29-year-old woman whose name was given as Amelia also told the group her son was beheaded in similar circumstances. Save the Children did not give the full identity of the witnesses or their real names to protect their identities.

“After my 11-year-old son was killed, we understood that it was no longer safe to stay in my village,” Amelia told the organization, explaining that they did not have time to properly bury her child before fleeing.

There have been numerous reports of beheading in the Cabo Delgado conflict, including of children. In November, Police Commander Bernardino Rafael told The Washington Post that at least 50 people had been decapitated in the first half of the month.

Chance Briggs, Save the Children’s country director in Mozambique, said that the reports of violence against children in Cabo Delgado “sicken us to our core” and said that staff had been brought to tears when speaking to witnesses.

“While the world was focused on covid-19, the Cabo Delgado crisis ballooned but has been grossly overlooked,” Briggs said.

The conflict in Cabo Delgado, a region in the northeast corner of Mozambique that is rich in oil and gas, intensified significantly last year. Much of the worst violence has been attributed to al-Shabab, a local Islamist group that does not have known links to the better known Somali group with the same name.

Security experts have voiced concern about the arrival of foreign fighters who used techniques similar to those found in conflicts in Syria, Afghanistan and Iraq.

U.S. officials said last year that the core Islamic State militant group provides fighters in Mozambique with training and other resources after formally adopting al-Shabab as the Mozambican wing of its Central Africa Province in June.

The Biden administration designated al-Shabab as a “foreign terrorist organization” last week and imposed sanctions on the group. The United States has also pledged to send military specialists to train the Mozambican army.

Of the more than 2,600 people who have died in the conflict since it began in 2017, roughly half were civilians deliberately targeted, according to the Armed Conflict Location and Event Data Project.

It isn’t only al-Shabab that has been accused of war crimes. Earlier this month, Amnesty International accused not only the militant group of unlawful killings but also government forces and a private military force allied with them, the Dyck Advisory Group.

Soldiers working with the South African contractor had broken international law by “firing indiscriminately into crowds, attacking civilian infrastructure, and failing to distinguish between military and civilian targets,” said Deprose Muchena, Amnesty International’s regional director.

Briggs said that now much of the concern was not only about the violence, but the enormous risks being placed on people displaced by the conflict.

“A major concern for us is that the needs of displaced children and their families in Cabo Delgado far outweigh the resources available to support them,” Briggs said, adding that nearly a million people were now facing severe hunger as a result of the conflict.