Witnesses said the military and police fired when protesters had taken a break from holding a vigil at the Republican Guards headquarters to say their morning prayers. Morsy is reportedly detained there after his arrest Wednesday.
The health ministry put the number of fatalities at 42, and said 322 others were wounded.
The military offered a different version. It said it was forced to fire when an “armed terrorist group” tried to raid the headquarters. An interior ministry statement said two security force members died in the clashes.
The Monday morning violence further deepened a crisis in the country — the Arab world’s most populous — where Morsy supporters have been squaring off daily with the military.
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