ALEPPO, Syria — Away from the Geneva peace talks and the give and take between the stakeholders of the Syrian crisis, Aleppo, the country's commercial hub, is witnessing the most crucial turning point at the national level since the outbreak of the revolution on March 15, 2011.

Feb. 1 was the zero hour chosen by the regime forces and their allies to launch a large-scale offensive against rebel-controlled areas in the northern Aleppo countryside. The entire city of Aleppo was shaken by the thunderous sound of artillery targeting the villages of the northern countryside, while Russian fighter jets filled the airspace.

These battles are unlike any others. They are the fiercest and bloodiest yet, for regime forces are attacking rebels at the heart of their areas of control, spurring them into all-out defense.

The northern countryside of Aleppo is a stronghold of the Free Syrian Army, having served as a starting point for the FSA to enter the city in July 2012. However, the map has become extremely intricate with four major players sharing control: the opposition made up mainly of the FSA, the regime and its allies, the Syrian Democratic Forces and the Islamic State.