According to Press TV, the London-based human rights group released a 34-page report on Friday, saying all sides in the fighting were guilty of violations.
The report said the Takfiri terrorists had committed unlawful killings, hostage-taking, pillage, and had mistreated prisoners in Marawi, which is located on the southern island of Mindanao.
The report, entitled “The Battle of Marawi: Death and destruction in the Philippines,” said the terrorists used child soldiers and singled out Christians for attacks.
Some survivors said hostages had been executed or physically abused and forced into labor and used as human shields, the report said.
Some hostages, who had managed to escape, said that they had been detained and tortured by security forces, who suspected them to be militants.
“I was punched and kicked,” the report quoted a survivor as saying. “They tied our hands and feet with electrical wire… The military was angry because 13 of their men were killed.”
Marawi had been the scene of fierce fighting between the Philippine forces and the terrorists since May 23. The terrorists occupied Marawi after taking control of the city’s central business district. They ransacked banks and shops and looted houses.
Last month, the Philippine government declared the city fully liberated.
The violence has displaced hundreds of thousands of residents and left at least 1,131 people dead, including 919 militants and 165 soldiers and police officers.
The Amnesty investigation, which was based on interviews with 48 witnesses from September until early November, cited at least 10 separate incidents where at least 25 Christians had been executed by the terrorists.
The rights group described the executions as war crimes.