Monitors: IS attack in northeastern Syria kills at least 22

This undated image posted online Monday, May. 1, 2017, by supporters of the Islamic State militant group on an anonymous photo sharing website, purports to show an Islamic State fighter firing his weapon during clashes with U.S.-backed Kurdish-led Syrian Democratic Forces, in the northern Syrian province of Raqqa. The Britain-based Syrian Observatory for Human Rights and Kurdish activists said Tuesday, May 2, 2017, that a surprise attack in northeastern Syria carried out by IS has killed over 20 people, including displaced civilians. Arabic banner reads, "Targeting gatherings of the infidel PKK with automatic weapons north of the province." (Militant Photo via AP) (The Associated Press)

This undated image posted online Monday, May. 1, 2017, by supporters of the Islamic State militant group on an anonymous photo sharing website, purports to show an Islamic State fighter firing his weapon during clashes with U.S.-backed Kurdish-led Syrian Democratic Forces, in the northern Syrian province of Raqqa. The Britain-based Syrian Observatory for Human Rights and Kurdish activists said Tuesday, May 2, 2017, that a surprise attack in northeastern Syria carried out by IS has killed over 20 people, including displaced civilians. Arabic banner reads, "Targeting gatherings of the infidel PKK with automatic weapons north of the province." (Militant Photo via AP) (The Associated Press)

This undated image posted online Monday, May. 1, 2017, by supporters of the Islamic State militant group on an anonymous photo sharing website, purports to show an Islamic State fighter firing his weapon during clashes with U.S.-backed Kurdish-led Syrian Democratic Forces, in the northern Syrian province of Raqqa. The Britain-based Syrian Observatory for Human Rights and Kurdish activists said Tuesday, May 2, 2017, that a surprise attack in northeastern Syria carried out by IS has killed over 20 people, including displaced civilians. Arabic banner reads, "Targeting gatherings of the infidel PKK with automatic weapons north of the province." (Militant Photo via AP) (The Associated Press)

A Syrian war monitoring group and Kurdish activists say a surprise attack in northeastern Syria carried out by the Islamic State group has killed at least 22 people, including displaced civilians.

They say the attack took place early on Tuesday after militants sneaked into the village of Rajm Sleibi, which houses a temporary displaced camp for people fleeing IS-held areas in Syria and Iraq.

The Britain-based Syrian Observatory for Human Rights says the attack included suicide bombers and heavy clashes with Kurdish-dominated U.S.-backed rebels who are fighting IS in Syria. The Observatory put the death toll at 24 killed.

A Kurdish activist put the death toll at 22, saying the victims were mostly women and children displaced from the conflict. He spoke on condition of anonymity fearing for his safety.