Egypt's opposition Muslim Brotherhood has accused the ruling National Democratic Party of obstructing parliamentary elections, as hundreds of the Islamist group's members are arrested.
Brotherhood members say police have intimidated voters, dispersed crowds with tear gas, and shut polling sites Saturday, where they suspect support for Islamist candidates.
Large contingents of riot police have been deployed for Saturday's run-off, in which voters in nine provinces are casting ballots where no candidate won a majority in the previous round of voting last Sunday.
In the two rounds of voting so far, Muslim Brotherhood candidates have had a strong showing, winning 47 of 444 elected seats. The NDP still maintains its dominance, however, having won 120 seats. But there is still one more round of voting to be held on Thursday.
The Brotherhood is banned as a political party, but endorses candidates who support the party's Islamist platform.