CAIRO — President Mohamed Morsi of Egypt and his allies refused to back down on their call to reinstate the disbanded Islamist-dominated Parliament on Monday, ignoring a veiled threat from the military and a rebuke from the country’s highest court, and ordering lawmakers to take their seats Tuesday at noon.

The deadline marked the second day of escalating tensions in the standoff between the newly elected Morsi, a member of the long-banned Muslim Brotherhood, and the vestiges of the former Mubarak regime, which still control Egypt’s military and judiciary.

‘‘It’s quiet for now, but wait until tomorrow,’’ said a kiosk vendor outside the Parliament Building on the evening before the expected showdown.

No extra troops were in evidence around the building. Police in regular uniforms manned the gates and sat in groups on surrounding sidewalks.

A week into his term, Morsi has quickly brought to a head the central dispute between the factions, the abrupt dismissal of the first post-revolution Parliament by the then-ruling military council and the Supreme Constitutional Court.

The confrontation emerges just days before an expected weekend visit by Secretary of State Hillary Rodham Clinton.

As Egypt struggles to find its footing as the Arab world’s newest — and largest — democracy, Morsi’s aggressive opening moves make it more likely that public confrontations between the sides will follow. The confrontation emerges just days before an expected weekend visit by Secretary of State Hillary Rodham Clinton.

In Tahrir Square, the center of last year’s historic popular uprising, Morsi supporters on Monday waved signs cheering his actions. And some Brotherhood members called for a mass march to support the lawmakers’ return to Parliament.

There was a modicum of civility between the two sides Monday, when Morsi appeared at a military graduation ceremony as the guest of Field Marshal Mohammed Hussein Tantawi, leader of the Supreme Council of the Armed Forces.

As the two leaders watched the marching cadets, they exchanged a few words and laughs, but they mostly looked on somberly.

Outside the event, both sides dug in on the standoff that began with Morsi’s decree Sunday annulling the Constitutional Court’s ruling and ordering Parliament’s return.

The court responded Monday with a warning that its June 14 ruling against the Legislature was ‘‘final and binding,’’ according to state television reports. Additionally, the court’s chief, Maher el-Beheiry, told Reuters the court would immediately begin reviewing Morsi’s attempt to reinstate Parliament.

The military council went into a closed emergency session Sunday. On Monday, it issued a statement read on state television warning Morsi to adhere to the court’s ruling and respect the constitution. The statement left little doubt that Morsi’s decree caught the generals off-guard and that the move was not part of a negotiated power-sharing deal.

In the meantime, other participants in Egypt’s fractured political scene warily staked out positions on what could be the next defining dispute in the country’s struggles to emerge from decades of dictatorship.

Brotherhood supporters, and some members of the coalition of youth activists that helped sparked the Tahrir uprising, cheered Morsi for standing up for a legislature they view as freely and fairly elected.

But several candidates from the just-completed presidential election deplored the president’s action as a power grab. Even some opponents of ousted president Hosni Mubarak — liberals and secularists — saw Morsi’s actions as an end-run that threatened the country’s judicial integrity.

‘‘The executive decision to overrule the Constitutional Court is turning Egypt from a government of law into a government of men,’’ read a tweet from Mohamed ElBaradei, the Nobel Prize-winning former diplomat who briefly considered a run for the presidency last year.

The speaker of the disbanded Parliament, Saad el-Katatni, said its lower chamber, the People’s Assembly, would convene Tuesday. The court’s ruling did not cover Parliament’s upper chamber, known as the Shura Council, which is largely powerless.

Both Morsi and Katatni are longtime members of the Muslim Brotherhood, which holds the majority of parliamentary seats.

Yasser Ali, a spokesman for the president, said Monday that Morsi’s decision did not violate the court’s ruling, according to the official Middle East News Agency.

In a separate report, the agency said the court was scheduled to look into several cases Tuesday questioning the legality of Morsi’s decision to reconvene Parliament.

The constitution that was in effect under Mubarak’s 29-year rule was suspended after his ouster. A new and permanent constitution has yet to be drafted, and that is not expected before late this year.

Since the departure of Mubarak, the ruling generals have come under criticism for being slow to hand over power to a civilian administration. After last month’s election, the military council agreed to hand over control to Morsi on June 30, but it also issued a decree giving itself far-reaching powers until a new constitution is drafted.

The Muslim Brotherhood, which was repressed under secular regimes, has emerged as the most powerful political force in Egypt after the revolution. However, many in Egypt who are tired of political domination by the military are also distrustful of the Brotherhood, a secretive fundamentalist movement that ultimately wants to create a more Islamic state.

In ordering that Parliament be reconvened, Morsi also called for new parliamentary elections within 60 days of the adoption of a new constitution.