Residents who reside in the long road that connects to Mogadishu and Afgoye said they saw hundreds of fighters walking from the side of Afgoye town to Mogadishu on Tuesday night.
The move comes as the Somali government was preparing to attack the rebels and clear from the country.
Residents in Deynile district in Mogadishu say the fighters made bases in the district where they have erected mortars.
The vehicles known as techincals were escorting the al Shabaab militias who were trained in bases in south western Somalia.
The people in Mogadishu have expressed concern about the troop movement of the Somali government soldiers and the Islamist rebels in the capital.