Opposition parties called for military action against the central government . Heavily armed tribesmen loyal to the anti - government Ahmar tribe have been attacking Sanaa . More than 200 pro - government heavily armed troops are stationed in the outskirts of town .
Opposition leaders call for military action against the Saleh government . Heavily armed tribesmen loyal to the anti-government Ahmar family have been entering Sanaa . More than 2,000 pro-government heavily armed tribesmen are stationed in the outskirts of Sanaa .