Cairo (CNN) -- Egypt's Islamists claimed victory in the first round of parliamentary elections since President Hosni Mubarak was forced out of office in February.
The relatively moderate Muslim Brotherhood's Freedom and Justice Party on Wednesday said on its website that it had won 34 seats in the runoff election.
Hardline Al Nour Salafi Party won five seats, according to its website.
Voters went to the polls in the first round of elections on November 28 and 29, and the runoff Monday and Tuesday.
The strong performance of Islamist parties raised eyebrows in some Western capitals.
On one hand, analysts say, the West is inclined to support popular Arab Spring movements that have toppled dictators and ushered democracy into the region. On the other hand, they worry about the ascension of radical Islamist movements in a region of critical interest to the United States and its allies.
"I don't think any Western government is happy about the result of the elections," said Marina Ottaway, a Middle East analyst at the Carnegie Endowment for Peace.
While the Muslim Brotherhood has pledged to respect minority rights and work with liberal parties, there have been concerns on the success of al-Nour, a Salafist party that supports broader application of strict Islamic law in Egypt.
The vote results came as military rulers granted the newly-appointed prime minister most powers of the president Wednesday.
Prime Minister Kamal Ganzouri then swiftly swore in his Cabinet.
Ganzouri was given all presidential powers except control over the military and the judiciary, said Lt. Col. Amr Imam, the armed forces spokesman.
"The new national government will be the salvation government of the January 28 revolution," Ganzouri said on state television Tuesday.
The new Cabinet will serve until the presidential elections.
Opposition parties have criticized the transfer of power.
The transfer amounted to "nothing but a political maneuver" by the country's military rulers "to attempt to appease the public opinion on the street after they have failed in running in the country during this interim period, said Ahmed Abu Baraka, the political adviser of the Muslim Brotherhood's Freedom and Justice Party.
"This new Cabinet will have to live up to the expectations of the revolution and only has a limited time before it's either reinstated again or replaced depending on their performance, and only the Egyptian people are to judge this," he said.
Rami Shaath, a member of the Egyptian Revolutionary Alliance, another opposition party, also had harsh words.
Giving "these so-called presidential powers to an 80-year-old prime minister and former member of Mubarak's NDP party do not mean anything to us," Shaath said. "He was chosen by the Supreme Council with no political base from Tahrir. When we demanded a national salvation government, we wanted a representative from the revolutionaries, not a puppet that serves the goals of the military who do not have right to choose him anyway."
Shaath said the Supreme Council will "continue to serve the need of the U.S. in the region" over citizen demands.
CNN's Mike Pearson and Yousuf Basil, and journalist Mohamed Fadel Fahmy contributed to this report