CAIRO (Reuters) - Egypt will hold a presidential election in late March, authorities said on Monday, starting the countdown toward a likely second term in office for incumbent Abdel Fattah al-Sisi.

Sisi has yet to announce his candidacy for the ballot, which was scheduled for March 26-28.

But he is widely expected to run, having won a landslide victory in the previous election in 2014, the year after - as a military commander - he led the overthrow of elected president Mohamed Mursi of the Muslim Brotherhood.

The national election commission said candidates must register between Jan 20-29 and that, in the event of no single participant winning a majority first time around, a run-off would be held on April 24-26.

The election will be Egypt’s third since the 2011 uprising that ended strongman Hosni Mubarak’s long rule.

Former prime minister Ahmed Shafik, who was seen as the most serious potential challenger to Sisi’s rule, said on Sunday he was no longer considering running.

Shafik returned to Egypt from the United Arab Emirates in December after announcing his intention to run, setting off a firestorm of criticism from state-aligned media and speculation that he was being held by authorities in a Cairo hotel.

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Sisi’s critics say his popularity has been dimmed by austerity reforms, security problems and a crackdown on dissidents.

His allies dismiss accusations of rights abuses, saying his measures are needed for security in the face of an Islamist insurgency in the North Sinai region that has expanded to include civilian targets.

Another presidential hopeful, rights lawyer Khaled Ali, faces a potential three-month prison sentence handed down in September for public indecency over an alleged rude hand gesture he made outside a courthouse last year.

He may be disqualified from standing if he loses his appeal on March 7.

Ali gained prominence in January last year when he won a case that nullified a government transfer of two Red Sea islands to Saudi Arabia, a deal that had prompted mass protests.

Lasheen Ibrahim, the judge heading the commission, told a news conference it would “spare no effort in running elections in accordance with the highest standards of fairness and international transparency.”

First round results will be announced on April 2 and, in the event of a run-off, final ones on May 1.