By Marwa Awad
CAIRO (Reuters) - Egypt's Muslim Brotherhood, doing well in parliamentary elections, said on Thursday it would shun a new council set up by military rulers to help oversee the drafting of a new constitution.
The popular Islamist group said it feared the body, which will include politicians, presidential candidates and youth representatives, would usurp the authority of the new parliament and become a permanent fixture in Egypt.
The army, which took charge of the country in February following the ousting of President Hosni Mubarak, is due to unveil the council formally later in the day.
A source close to the project told Reuters that if it proves successful its mandate could be extended once the military has handed full power to a civilian president in 2012.
"If this body succeeds to resolve national issues, it could possibly evolve into a national defense committee and stay in force even after a president is elected," the source said, making clear that army figures could join the group later.
It was not clear how such a body would fit beside the new parliament and a senior member of the Muslim Brotherhood's Freedom and Justice Party (FJP), which has taken a firm lead in early polling over recent weeks, said the group would boycott the council.
"After participating in the initial negotiations ... it became apparent that the advisory group will have a mandate beyond the transitional period headed by the military council," said the FJP's Mohamed al-Katatni.
He said this would "detract from the (parliament) and intervene in the formation of the founding assembly to draft the constitution."
The new parliament's primary task will be to pick a 100-strong body to write the new constitution, but Egypt's army wants its civilian advisory group and the cabinet to help set the guidelines for the ambitious project.
Analysts say the advisory group could become another means for the military to influence parliament after it cedes power following presidential elections next June.
Clashes between police and protesters demanding that the army cede power have killed over 40 people over the last month.
"The main goal of this advisory council is to co-opt the forces of the revolution further. It will try to pick up where the Silmi's document on the constitution left off," said Khalil Anani, a political analyst.
Silmi's document is a now defunct constitutional proposal that the military council floated in November, which critics said would shield the army from civilian control and allow it to defy the new government.
The advisory council has already met Chief-of-Staff Sami Annan for initial discussions on key issues, such as economic aid, which will be determined after parliament convenes.
"The advisory council has already discussed and offered its views on U.S. economic and military aid to Egypt ... and to what extent Egypt can forgo economic aid," the source said, refusing to comment on what could happen to the military aid.
Egypt receives $1.3 billion from Washington in military aid.
(Writing by Marwa Awad; Editing by Crispian Balmer and Richard Meares)