Three top candidates in Egypt's presidential race filed appeals to the election commission ahead of the deadline Sunday, alleging violations in the first round vote that they say could change the outcome.

The appeals alleging fraud are likely to enflame an already explosive race.

Preliminary results from last week's election placed Muslim Brotherhood candidate Mohammed Morsi and Hosni Mubarak's last prime minister, Ahmed Shafiq, as the two candidates entering a June 16-17 runoff. Thirteen candidates were on the ballot.

Shafiq, who placed second after Morsi, said votes cast for him in one province were not included in the ballot count.

Many voters reject both front-runners as polarizing extremists. Young, liberal secularists who led the popular rebellion that overthrew longtime leader Hosni Mubarak last year failed to place a candidate in the runoff.

A large portion of the vote _ more than 40 percent _ went to candidates who were seen as more in the spirit of the uprising _ neither for the Brotherhood nor for the so-called "feloul," or "remnants" of the old autocratic regime _ but those votes were mostly divided among the two candidates who placed third and fourth.

The top finisher, the Brotherhood's Morsi, received only about 25 percent of the vote, according to preliminary results.

Hamdeen Sabahi, a socialist and a champion of the poor who made a surprisingly strong showing, called for a partial vote recount after he placed third by a margin of 700,000 votes after Shafiq.

Sabahi's campaign said in a statement Sunday that its representatives met with the elections commission to request that official results not be announced until the eligibility of voters in five provinces is reviewed.

Official first-round results are expected Monday or Tuesday.

Abdel-Moneim Abolfotoh, a moderate Islamist who finished fourth, also filed an appeal Sunday. His lawyer said the campaign has proof that votes were cast on behalf of dead people, and in other cases, bribes were paid for votes.

Overall, the presidential election was considered the country's freest and most transparent in decades. Judges were present at each polling station. International and local monitors, as well as journalists and the candidates' representatives, were allowed to oversee the process in stark contrast to elections under Mubarak.

On Saturday, ex-President Jimmy Carter said his center was restricted in its monitoring mission, but the process was generally acceptable.

The Carter Center said in its report that the quality of the polling process was generally "good", but that election authorities prohibited access to the final aggregation of national results, "undermining the overall transparency of the process."

Also Sunday, a criminal court convicted Mubarak's former chief of staff of corruption, sentencing him to seven years in prison and fining him $6 million, Egypt's official news agency reported.

Zakaria Azmi, who was also a lawmaker and a senior member of Mubarak's ruling National Democratic Party, used his position to make illicit gains of $7 million, according to the court ruling carried by Egypt's official Middle East News Agency.

The verdict against Azmi comes less than a week before a court is due to issue its verdict in the trial of Mubarak, who faces charges of complicity in the killing of protesters during the popular uprising last year. Mubarak, along with Gamal and his other son, Alaa, also faced corruption charges.

Mubarak could receive the death penalty if convicted in the killing of protesters.