The Muslim Brotherhood says it has won at least 33 seats in the first round of national assembly elections in Egypt.
Brotherhood campaigners have been given unprecedented freedom
Initial results announced at some polling stations following a round of run-off voting on Tuesday indicated similar gains.
If confirmed officially, the results would more than double the seats held by the Islamic political group.
The organisation is banned in Egypt but tolerated by the authorities and fields electoral candidates as independents.
Opposition candidates again alleged that there had been widespread fraud by President Hosni Mubarak's governing National Democratic Party.
The NDP currently controls more than 400 of the assembly's 454 seats; 164 seats were voted on in the first round in Cairo and some other provinces.
Correspondents say the elections are not expected to bring a major change in the balance of power.
A Brotherhood spokesman said the group's performance, apparently winning a fifth of seats, "confirms in an unquestionable way that the Egyptian people stand behind the Brotherhood and that the Brotherhood really do represent the strongest social and political group in Egypt".
The elections are being held in three two-round phases.
The second round, which includes the northern city of Alexandria, will be held on 20 November; the third round will go ahead on 1 December.