BEIRUT: The Islamic State group (IS) has executed nearly 1,500 people in Syria in the five months since it declared the establishment of a “caliphate,” a monitoring group said Monday.

“The Syrian Observatory for Human Rights has documented the execution of 1,429 people since the IS announced its ‘caliphate’ in June,” the group’s director, Rami Abdel Rahman, said.

The majority of IS’s victims in Syria have been civilians, he said.

“Of the total number of people beheaded or shot dead in mass killings by IS, 879 have been civilians, some 700 of them members of the Shaitat tribe.”

The Sunni Shaitat tribe, from the eastern province of Deir El Zor, rose up against the militant group in mid-2014.

Another 63 of the dead were members of other rebel groups or the rival Al-Nusra Front, which has fought IS in the north and east, Abdel Rahman said.

“Another 483 were regime soldiers, while four others were IS members” accused of corruption or other alleged offenses, Abdel Rahman said.

Meanwhile, a young Frenchman was one of the militants in video that appeared to show the beheading of Syrian soldiers and a US aid worker, prosecutors said on Monday.

The man is believed to be 22-year-old Maxime Hauchard from a small village in Normandy in northern France.

He is thought to have “left for Syria in August 2013 after a stay in Mauritania in 2012,” Interior Minister Bernard Cazeneuve told reporters.

Separately, Iraqi TV said the chairman of the US Joint Chiefs of Staff, Army Gen. Martin Dempsey, has arrived in Baghdad, his first visit to Iraq since a US-led coalition began a campaign of airstrikes targeting the group.

Dempsey, a veteran of the Iraq war, arrived Saturday on a previously unannounced visit.

His trip comes two days after he told Congress that the United States would consider dispatching a modest number of American forces to fight with Iraqi troops.