Egyptian officials say they will announce results of the country's first stage of parliamentary elections on Thursday, a day later than originally planned.

State media reports announced the change on Wednesday but did not specify what caused the delay.

Earlier Wednesday, Egypt's powerful Muslim Brotherhood said its bloc was in the lead following voting on Monday and Tuesday. The group challenged Egypt's military rulers by claiming high voter turnout signified a popular demand for civilian rule.

Egypt's military chiefs hailed round one as a success, claiming the high turnout meant protesters camped in Cairo's Tahrir Square and those demonstrating elsewhere do not represent most Egyptians.

At least 42 people were killed and more than 3,000 injured in clashes between protesters and security forces in the lead-up to the election.

Full tallies for the lower house will not be announced until January, after two more rounds of voting in the rest of the country. The entire election will not be over until March.

U.N. Secretary General Ban Ki-moon congratulated Egyptians for what he called their enthusiastic participation at the ballot box.

U.S. Secretary of State Hillary Clinton congratulated Egyptians on a “peaceful, successful start to their election process.”

The historic elections will determine whether Egypt moves away from decades of authoritarian secular rule, and down a different — possibly Islamic — path.