Beirut: At least 554 people have died since the Islamic State's (IS) advance on the northern Syrian Kurdish city of Kobane began in mid-September, the Syrian Observatory for Human Rights said Saturday.

At least 20 of those killed have been civilians who died in Kobane -- located on the border with Turkey -- and villages on its outskirts. Seventeen of those victims were executed by the Sunni militants, four of whom were decapitated.