The Egyptian parliament’s first task will be to ratify about 300 presidential decrees issued since June 2014. (Namer Galal/European Pressphoto Agency)

Egypt’s first legislature in more than three years, a 596-seat chamber packed with supporters of President Abdel Fatah al-Sissi, held its inaugural session Sunday, signaling the completion of a political road map announced after the 2013 military overthrow of an elected Islamist president.

The assembly, elected in November and December, is the first legislature since Sissi, as military chief, led the ouster of President Mohamed Morsi amid mass protests against the Islamist leader and his Muslim Brotherhood. The new parliament replaces an ­Islamist-dominated one dissolved by a court ruling in June 2012.

The new chamber’s first task will be to ratify about 300 decrees issued by Sissi since taking office in June 2014 and by interim president Adly Mansour before him. Under the constitution, these decrees must be ratified within 15 days of the start of the inaugural session. Failure to do so will result in the automatic repeal of the laws.

The decrees include a law severely restricting street demonstrations and an anti-terrorism law that curbs press freedoms and gives police sweeping powers.

Sunday’s session was supposed to be a mostly procedural one. But heated arguments between lawmakers broke out when an outspoken member, Murtada Mansour, strayed from the text of the oath to avoid endorsing the Jan. 25, 2011, uprising against autocrat Hosni Mubarak.

Mansour, a Sissi supporter and president of one of Egypt’s top soccer clubs, changed the part of the oath in which lawmakers pledge respect for the constitution, saying instead that he will respect the “clauses of the constitution,” thus avoiding implicit support for the charter’s prologue. That section of the document contains praise for the 2011 revolt as well as the “June 30 revolution,” a reference to the wave of street demonstrations that led to Morsi’s ouster.

The dispute reflects an ongoing argument in Egypt regarding the legitimacy and legacy of the 2011 uprising. Many pro-Sissi politicians and media figures now deem the 2011 revolt a mistake — fueled and funded by external powers and foreign agents seeking to weaken Egypt. Other Sissi supporters regard the ouster of both Mubarak and Morsi as legitimate revolutions.

“I don’t recognize January 25. That is my prerogative,” an angry Mansour said over the shouts of other lawmakers.

After Morsi’s overthrow, Sissi announced three steps in Egypt’s transition to democracy: the adoption of a new constitution and presidential and parliamentary elections.

But the process has unfolded against the backdrop of a harsh crackdown on Islamists and secular and leftist pro-democracy activists who fueled the 2011 uprising. Thousands have been jailed, and hundreds of Islamists were killed in clashes with security forces in 2013 and 2014. The Muslim Brotherhood is officially branded a terrorist group.

Turnout for last year’s parliamentary elections was about 30 percent, and most of those elected to the assembly support the president.

On Sunday, Sissi vowed to support the chamber and respect the separation of powers, according to a statement issued by his office. Under the constitution adopted in 2014, perhaps Egypt’s most liberal, the legislature has the right to impeach the president and sack the prime minister, albeit under strict conditions.

A pro-Sissi coalition in parliament, called Supporting Egypt, has the backing of 366 lawmakers, according to its leader. Law professor Ali Abdel-Al of the coalition was elected speaker of the legislature, winning 401 votes.

Sissi, who is expected to address the chamber later this month, has been focused on restoring security and reviving the nation’s ailing economy.

Egypt is grappling with an increasingly potent Islamist insurgency, centered in the northern part of the Sinai Peninsula, which claimed the downing of a Russian passenger plane over Sinai in October that killed all 224 people aboard and led to widespread flight cancellations, dealing a major blow to the vital tourism industry.

Egypt’s economy has been kept afloat by billions of dollars from its oil-rich Persian Gulf Arab backers. Still, the local currency, the pound, has been under growing pressure.