(FOXNEWS) — Egypt’s new president moved to assert his authority Saturday by naming a chief rival of ousted leader Mohammed Morsi as interim prime minister and holding crisis talks with security officials on efforts to reclaim control of the streets, Fox News confirms.

The steps by Adly Mansour are likely to deepen the defiance by Islamist opponents who have turned parts of Cairo into vigilante-guarded strongholds and have issued blood oaths to battle until Morsi is restored.

After a night of clashes that claimed at least 36 lives and injured more than 200, both sides appeared to be preparing for the possibility of more violence as Egypt’s political unraveling increasingly left little room for middle ground or dialogue. Only a fraction of Cairo’s normally heavy traffic was on the streets amid worries that violence could flare up again.

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