§ Of the Ruin of Doriath The Silmarillion

Then great was the wrath and lamentation of the Dwarves of Nogrod for the death of their kin and their great craftsmen, and they tore their beards, and wailed; and long they sat taking thought for vengeance. It is told that they asked aid from Belegost, but it was denied them, and the Dwarves of Belegost sought to dissuade them from their purpose; but their counsel was unavailing, and ere long a great host came forth from Nogrod, and crossing over Gelion marched westward through Beleriand.