Egypt's Presidential Election Commission said it would delay the announcement of a winner in the weekend contest as it pressed forward with an investigation into fraud claims.

The commission's decision, reported by the state news agency, didn't say when it would announce results, which had been expected to come on Thursday. The delay and the unusually vigorous investigation deepened suspense in a country on edge as it waited to learn who will be its first freely elected president.

Conflicting reports about the deteriorating health of ousted President Hosni Mubarak, who was briefly pronounced 'clinically dead' by state media late on Tuesday before authorities called that an exaggeration, have heightened tensions.

The Election Commission, state media and a civilian board advising the military all appeared to be pushing back against victory claims made earlier in the week by the Muslim Brotherhood. The group based its claims on aggregations of vote totals collected by their monitors at polling centers across the country.

Brotherhood candidate Mohammed Morsi's campaign said its vote totals show Mr. Morsi won 52% of the vote in the weekend contest, with 900,000 more votes than his rival, ex-Prime Minister Ahmed Shafiq. To back up its claim, the Brotherhood released on the Internet 426 pages of what appear to be photocopied certified elections results from each of Egypt's more than 13,000 polling centers.

An association of independent judges who monitored the weekend vote also endorsed the Brotherhood's totals on Wednesday. 'Our numbers were very close to the Brotherhood's campaign numbers because we all get them from the same source, the polling stations,' the head of the group, Judge Zakaria Abdel Aziz, said. 'There won't be major discrepancies unless the commission cancels votes.'

Two international poll monitors from the Carter Center, which observed the vote, said the Brotherhood's figures appeared air tight.

Mr. Shafiq's campaign has claimed victory with a similar percentage of the vote. His spokesman said it was the election commission's job to publish results, and the rest was just the 'opinion' of the parties. Mr. Shafiq was confident he had won but would accept the result no matter the outcome, the spokeman said.

On Wednesday, the commission summoned officials from both candidates' campaigns to answer questions about allegations by them and against them. A Morsi campaign official said the group's lawyer presented its copies of vote totals, signed by the judges, for every polling station across Egypt.

State media reported that prosecutors had arrested three heads of polling centers around the country to question them over allegations of electoral fraud. Media also reported that at least seven employees of a state printing agency were being interrogated for allegedly printing thousands of ballots with a vote for Mr. Morsi already checked off.

The Electoral Commission is staffed by six judges appointed by Mr. Mubarak, and is headed by a judge who made a career presiding over the country's state security courts, which were used to prosecute political dissidents.

Charles Levinson / Matt Bradley / Tamer El-Ghobashy