"It is with profound sadness that we are confirming today that two members of Save the Children's staff were among at least 35 people, including women and children, who were killed on Friday 24th December in an attack by the Myanmar military in Kayah State," the charity said in a statement.

On Saturday, photos appeared on social media purporting to show two burnt-out trucks and a car on a highway in Hpruso township in eastern Kayah state, with the charred remains of bodies inside.

Local anti-junta fighters and a monitoring group accused junta troops of carrying out the attack in Hpruso after clashes with dissidents in the area.

The two men had been "working on a humanitarian response in a nearby community when they were caught up in the attack," the charity said.

"The military forced people from their cars, arrested some, killed many and burnt the bodies."

The Myanmar military has denied the claims.

Myanmar has been in chaos since the February coup, with more than 1,300 people killed in a crackdown by security forces, according to a local monitoring group.