Given the following passage  "Accusing the rebels of being "drugged" and linked to al-Qaeda, Gaddafi proclaimed that he would die a martyr rather than leave Libya. As he announced that the rebels would be "hunted down street by street, house by house and wardrobe by wardrobe", the army opened fire on protests in Benghazi, killing hundreds. Shocked at the government's response, a number of senior politicians resigned or defected to the protesters' side. The uprising spread quickly through Libya's less economically developed eastern half. By February's end, eastern cities like Benghazi, Misrata, al-Bayda and Tobruk were controlled by rebels, and the Benghazi-based National Transitional Council (NTC) had been founded to represent them.",  answer the following question. Note that the answer is present within the text.  Question: The rebels gained representation because of what event causing the uprising?
A:
the army opened fire