ISIS terrorist in Raqqa, Syria
ISIS terrorist in Raqqa, SyriaReuters

The Islamic State (ISIS) group has killed 1,878 people in Syria during the past six months, the majority of them civilians, a British-based Syrian monitoring organization said on Sunday, according to Reuters.

ISIS also killed 120 of its own members, most of them foreign fighters trying to return home, in the last two months, said the Syrian Observatory for Human Rights.

The group has taken vast parts of Iraq and Syria and declared a caliphate in territory under its control in June. Since then it has fought the Syrian and Iraqi governments, other insurgents and Kurdish forces.

Rami Abdulrahman, the head of the Syrian monitoring group, told Reuters that ISIS killed 1,175 civilians, including eight women and four children. He said 930 of the civilians were members of the Sheitaat, a Sunni Muslim tribe from eastern Syria which fought Islamic State for control of two oilfields in August.

Reuters cannot independently verify the figures but Islamic State has publicized beheadings and stoning of many people in areas it controls in Syria and Iraq. These are for actions it sees as violating its reading of Islamic law, such as adultery, homosexuality, stealing and blasphemy.

ISIS has been accused of torturing and murdering prisoners, among them children and teenagers, and forcing Druze men to convert to Islam or die.

In one case, members of the group beheaded a person they said was a member of an Iraqi Shiite militia fighting for President Bashar Al-Assad, only to discover they had accidentally beheaded a fighter belonging to an allied rebel group.

In March, the group live-tweeted the amputation of a hand of a man charged with theft in the northern province of Aleppo.

The group has also released videos of executions of captured enemy fighters, activists and journalists.

It beheaded two U.S. journalists, and one American and two British aid workers this year in attempts to put pressure on an international coalition which has been bombing its fighters in Syria since September.

Abdulrahman, who gathers information from all sides of the Syrian conflict, said that Islamic State had also executed 502 soldiers fighting for Assad and 81 anti-Assad insurgents.

He said that 116 foreign fighters who had joined ISIS but later wanted to return home, were executed in the Syrian provinces of Deir Al-Zor, Raqqa and Hassakeh since November. Four other Islamic State fighters were killed on other charges, Abdulrahman said.