At least 17 people were killed in Egypt in clashes between police and backers of the banned Muslim Brotherhood, local media reported Saturday.
Friday's clashes left 10 people dead in Cairo. Others were killed in the southern city of Minya and the northern provinces of Alexandria, Ismailia and Fayoum, dpa reported.
The violence broke out after backers of the Islamist group took to the streets, defying a ban.
Authorities outlawed the Brotherhood in September and declared it a terrorist group in December.
Under Egyptian law, terrorism-related charges carry the death penalty.
The Interior Ministry said 235 Brotherhood followers were arrested in several areas of Egypt for possessing petrol bombs and firearms. Seventeen policemen were injured.
The group's backers have staged almost daily protests since July when the army deposed president Mohammed Morsi, a senior Brotherhood official.
Hundreds have been killed in violence since the military overthrew Morsi, the country's first democratically elected president.
The latest violence came ahead of a January 14-15 referendum on a draft constitution. Morsi's supporters reject the new constitution and said they will boycott the vote.