Militants from the jihadist group Islamic State of Iraq and the Levant (Isis) have reportedly executed at least 15 civilians, including six children, in the northern Syrian village of al-Taliliya.

Residents and local officials told Human Rights Watch (HRW) that the victims were Syrian Arabs who had been displaced from the countryside around the city of Aleppo.

According to HRW, the Isis Sunni insurgents are killing people in Syria as well as in Iraq, where they have seized the cities of Mosul, Tikrit, Sadiyah and Jalawla, displacing hundreds of thousands of people.

"While everyone is focused on Isis's advances in Iraq, they're also committing atrocities in Syria, including gunning down civilians," said Nadim Houry, deputy Middle East and North Africa director at HRW. "Isis flouts the law, executing civilians at will, while Russia and China paralyse UN Security Council action."

According to locals, Isis fought against Kurdish fighters from the People's Protection Units (YPG), on 28 May. The next day, Isis entered al-Taliliya and killed at least 15 civilians.

The Kurdish fighters were not in the village at the time.

Many residents refused to give further details on the violence as they were afraid of repercussions by Isis.

An elderly Syrian Arab woman who lost family members in the attack said: "We are afraid. If we talk they will come to our families and kill us.

"We do not have any connection with any side, not with Isis or the Kurds. We just work on our land. We want to stay safe on our land. I don't want to lose my two other sons."

One resident of a nearby village said she saw the bodies of at least five men and six or seven children, one of them an infant.

"When I got there I saw one old woman screaming and shouting that Isis had killed her entire family.

"I tried to calm her down. She took me inside and showed me her husband and two sons above 18 years old executed with gunshots to their heads or chest. The wife of her son was also executed."

Amnesty International also reported on the death of at least 15 civilians.

"Arab farming families were targeted, apparently for their perceived support of a Kurdish armed group, the YPG or because they were mistaken for Yezidi Kurds," Amnesty said.