By Asma Alsharif and Shadia Nasralla
CAIRO (Reuters) - Egypt will hold a presidential vote before parliamentary polls, President Adly Mansour said on Sunday, in a change to a political roadmap that could pave the way for the swift election of army chief General Abdel Fattah al-Sisi.
Parliamentary elections were supposed to be held first under the timetable drawn up after the army overthrew President Mohamed Mursi of the Muslim Brotherhood in July following mass protests against his rule.
The decision to revise the order of elections is likely to deepen tensions in Egypt, which is struggling to cope with waves of political violence. Forty-nine people were killed in anti-government marches on Saturday, the third anniversary of the popular uprising that toppled autocrat Hosni Mubarak.
"I have taken my decision to amend the roadmap for the future in that we will start by holding presidential elections first followed by the parliamentary elections," interim leader Mansour said in a televised speech.
Critics have campaigned for a change of the roadmap, saying the country needs an elected leader to direct government at a time of economic and political crisis and to forge a political alliance before potentially divisive parliamentary elections.
Sisi is expected to announce his candidacy for the presidency within days and win by a landslide. His supporters see him as a strong, decisive figure able to stabilize Egypt.
The Brotherhood accuses him of masterminding a coup and holds him responsible for widespread human rights abuses in a crackdown against the movement which has killed up to 1,000 Islamists and put top leaders behind bars.
While tough measures against the Brotherhood have nearly crippled it, security forces have failed to contain an Islamist insurgency. Militant attacks have raised fears for the stability of Egypt, of great strategic importance because of its peace treaty with Israel and control over the Suez Canal.
A new constitution voted in earlier this month cleared the way for a change in the order of the elections by leaving open the question of which should come first.
"It was an expected move amid the growing signs that Sisi is being groomed to become the next president," said Khaled Dawoud, a well-known liberal activist.
Mansour did not announce a date for the presidential vote. The constitution says steps towards holding the first of the elections should be begin no later than 90 days from the ratification of the document in mid-January.
Insurgents based in the Sinai Peninsula have stepped up attacks, killing hundreds since army chief Sisi ousted Mursi, Egypt's first democractically-elected president.
Gunmen killed three Egyptian soldiers in an attack on a bus in the Sinai on Sunday, the military said, prompting a warning from the army that it would eliminate the Brotherhood, which it blames for much of Egypt's political violence.
Anti-government demonstrations in Cairo on Saturday were attacked by supporters of the new political order and security forces, witnesses said. Of the 49 people killed, 22 Brotherhood supporters were shot dead with live rounds in one district of northern Cairo, security sources said.
The violence highlighted deep divisions that have flared often since the 2011 uprising that toppled Mubarak and raised hopes of a stable democracy.
In another attack in the lawless Sinai, five soldiers were killed on Saturday when an army helicopter crashed in the north of the peninsula in an operation against militants. Security sources said it was a missile attack, without giving further details. The army has not commented on the cause of the crash.
Militant group Ansar Bayt al-Maqdis (Supporters of Jerusalem) claimed responsibility for a rocket attack on a helicopter in a statement posted on the internet.
Egyptian authorities make no distinction between militant groups operating in the Sinai and the Brotherhood, which renounced violence in the 1970s but has been declared a terrorist group by the Egyptian government.
In a statement about the bus attack posted on Facebook, the army said: "We assure the Egyptian people of the great determination of its men to fight black terrorism and the complete elimination of the advocates of oppression and sedition and blasphemy from followers of the Muslim Brotherhood."
The soldiers were killed on their way back home from holiday when gunmen opened fire with automatic weapons and rocket-propelled grenades, security sources said.
Mansour suggested that Egypt, criticized by human rights groups for its hardline tactics against both Islamist and liberal opponents, was about to resort to tougher measures.
He said authorities would act swiftly to prosecute insurgents. "I have asked the President of the Appeals Court to expand judicial capacity in order to officiate speedy trials of terrorist cases," said Mansour, adding this should not violate the fundamental rights of citizens.
Such moves are likely to reinforce the view of government opponents that Egypt is returning to Mubarak's iron-fisted rule, or worse.
Mocking what has become known as Sisi mania - everything from T-shirts to posters to chocolates honor the general - the April 6 movement, which played a prominent role in igniting the revolt against Mubarak, criticized the change to the roadmap.
It used a play on words to describe it in a tweet: "PresSisi-dential elections".
(Additional reporting by Maggie Fick; Writing by Michael Georgy; Editing by Rosalind Russell)