Official results released Sunday confirmed decisive initial victories for Islamists in the first round of Egypt’s parliamentary elections.

Almost two-thirds of the ballots cast for parties in the elections last week were for candidates from religious blocs, with 24.4 percent of all votes going to the ultraconservative Salafist Nour party, whose candidates advocate a state that adheres to their ascetic brand of Islam.

The results reflect trends similar to those seen in parallel votes for individual candidates, whose tallies were announced late last week. There were few clear winners, and most races will be decided in runoff elections beginning Monday, but several contenders were from the political wing of the relatively moderate Muslim Brotherhood and will compete with Nour party candidates in many of the contests.

The fragmented liberal, secular and leftist parties and the remnants of the National Democratic Party, which was the ruling political bloc during the reign of now-ousted Hosni Mubarak, received far fewer votes, especially in rural areas.

In welcoming the results, the Muslim Brotherhood released a statement thanking the Egyptian people for the relatively calm elections and for giving “the great people of this homeland double the thanks for granting us their trust.”

Two additional rounds of voting are scheduled over the next three weeks for the lower house of parliament, followed by elections for the upper house, or Shura Council, which are not set to be completed until March. Some say that announcing partial results after the first of many rounds of balloting prejudices the vote.

“People might do protest votes or strategic voting to counterbalance the winners of the first round, or in a rural area where patronage counts for a lot, a local leader might decide he wants a Brotherhood member to represent him because it seems like that is the group that will hold sway,” said Shadi Hamid, director of research at the Brookings Doha Center. “It distorts results because people are not acting according to their natural voting desires.”

Some supporters of the parties that grew out of the movement that swept Mubarak from power in February hoped that the strong showing by Islamist parties would galvanize young, secular voters. “I am very optimistic that [secular, liberal groups] . . . will have more seats” in the next round, said Israa Abdel Fattah, a political activist.