Doubts have emerged over an initial naming of Egyptian opposition leader Mohamed ElBaradei as interim prime minister. Sectarian violence has worsened, with the Muslim Brotherhood calling for more protests.
Activists of the pro-reform Tamarod movement had said on that the Nobel Peace Prize winner ElBaradei would lead the transitional government ahead of elections.
"ElBaradei will head the government in the transitional period, during which early presidential elections will be held," the group announced on its Facebook page.
But, Egyptian state television later said an interim prime minister had not yet been chosen.
A spokesman for interim President Adly Mansour, Ahmed el-Musilamani, told reporters in Cairo shortly before midnight Saturday, local time, that there were several options for the job and the presidency had to take account of opposition to ElBaradei, reportedly from the ultraconservative Salafi el-Nour party.
El-Musilamani added, however, that ElBaradei was "the logical choice" among a list.
Earlier, named officials and state media had said ElBaradei would be appointed after members of Tamarod met Mansour.
Mansour was himself sworn in as head of state on Thursday the military's removal of Islamist President Mohammed Morsi who was elected last year.
ElBaradei, who won the Nobel peace prize in 2005 for his work with the International Atomic Energy Agency, became a prominent opponent of former dictator Hosni Mubarak.
In late June, ElBaradei had called on Morsi to resign after one year in office for the sake of national unity.
The naming of ElBaradei had been greeted with cheers among opponents of Morsi at Cairo's Tahrir Square and Ittihadiya presidential palace, but it was rejected by a senior Brotherhood official, Farid Ismail.
"We reject this coup and all that results from it, including ElBaradei," said Ismail.
Obama 'not aligned'
In Washington, the White House said US President Barack Obama had "reiterated that the United States is not aligned with, and does not support, any particular Egyptian political party or group."
His officials said Obama had made the remarks while consulting his national security team at his Camp David retreat, where he was spending the weekend.
The US gives some $1.3 billion (1 billion euros) in military aid each year to the Egyptian army.
Rise of sectarian violence
On Saturday, gunmen shot dead a 39-year-old Coptic priest in Egypt's Northern Sinai's provincial capital, el-Arish. Islamists have attacked churches in six cities since the coup, the Maspero Youth Coalition activist group reported. The priest becomes the 36th person killed since Morsi's removal from office Wednesday.
Saturday's attacks on checkpoints took place in al-Mahajer, al-Safaa in Rafah, Sheikh Zuwaid and al-Kharouba. The violence follows attacks that killed five police offers in el-Arish on Friday.
The country's clashes have accelerated since Mohammed Badie, the supreme leader of Morsi's Muslim Brotherhood, defiantly proclaimed that his followers would not give up street action until the toppled president returned to office.
Last year, the Brotherhood and its allies won majorities in both houses of parliament after the toppling of Mubarak, but failed to build a widespread consensus in the country as a whole. On Wednesday, the army declared that Morsi was no longer president and suspended the constitution.
rc/ipj (AFP, AP, Reuters)