Reuters. Mohamed Mursi warning stirs fears in Egypt opposition

Egyptian President Mohamed Mursi threatened on Sunday to take unspecified steps to "protect this nation" after violent demonstrations against his Muslim Brotherhood, using vague but severe language that the opposition said heralded a crackdown, Reuters reported.

In remarks following clashes outside the Brotherhood's Cairo headquarters on Friday, Mursi warned that "necessary measures" would be taken against any politicians shown to be involved in what he described as violence and rioting.

"If I am forced to do what is required to protect this nation, then I will do it. And I fear that I might be on the verge of doing it," Mursi said in a statement. He did not elaborate.

Mursi has faced increasing anger since the Brotherhood propelled him to power in a June election, and several spates of protest have turned into violent riots.

Mursi's opponents accuse him and the Brotherhood of seeking to dominate the post-Hosni Mubarak era and resorting to undemocratic police powers two years after autocrat Mubarak was brought down by popular protests.

One recent source of tension between Mursi and the opposition was his call for parliamentary elections based on a controversial election law. The vote, due to begin in late April, has been postponed by a court ruling and it is now not clear when it will happen.

Mursi's political supporters and opponents signed a document agreeing to renounce violence following riots in late January.

Mursi's opponents say they are committed to peaceful protest and have also accused the Brotherhood of using violence and inciting tension in the street. The Brotherhood says the opposition has done little to rein in its followers.