Coalition airstrike kills 15 civilians in northeast Syria
"15 civilians have been killed and another 20 injured in an international coalition airstrike that hit a bakery in al-Shaddadi," said Rami Abdulrahman, the UK-based group's director.
The IS media arm, Amaaq, posted a video online showing the complete destruction of the bakery and locals lifting bodies from the rubble.
Abdulrahman added that the air raid on the town coincided with an attack by the Kurdish-led Syrian Democratic Forces (SDF) on IS positions in al-Shaddadi, which has been under the control of militants since 2014.
Syrian news sources have reported that the SDF is preparing to launch a major offensive on al-Shaddadi in a bid to retake it from IS militants.
Liberating the town would cut off a supply route to the IS putative capital of Raqqa some 160 kilometres to the west.
SDF has made significant gains against IS in Hasakah since its formation in October 2015, retaking vast areas with the help of coalition air cover.
However, the international coalition airstrikes that started in September 2014 had resulted in the deaths of at least 332 Syrian civilians by 23 January 2016, according to the Syrian Observatory for Human Rights.