The Muslim Brotherhood said on Saturday it will contest up to half the parliamentary seats in elections scheduled for September.
But the group said it will not field a candidate for the position of president in an election due to held after the parliamentary vote.
The Muslim Brotherhood is regarded as the most organized political force in Egypt after the ouster of Hosni Mubarak in February and the dissolution of his National Democratic Party.
In a statement issued after a meeting of its decision-making shura (consultative) council, the group said it had decided to contest "between 45 and 50 percent of parliament's seats".
Since Mubarak's rule was ended by a mass uprising, the Brotherhood has stated that it does not seek power, and has said it will not seek the presidency or a majority in parliament.
The group is viewed with suspicion by Washington but is regarded as the only truly organized bloc in Egypt and reckons it could win up to 30 percent of votes in a free election.
Though formally banned under Mubarak, it was tolerated as long as it did not challenge his power. The Brotherhood is an Islamist group founded in the 1920s and has deep roots in Egypt's conservative Muslim society.
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