UPDATE: [July 3, 3:14 p.m.] Fireworks and cheering erupted in Tahrir Square after General Abdel Fattah al-Sisi, Egypt's military chief, announced that the military has suspended the country's Islamist-backed constitution and named Adli Mansour, the chief justice of the constitutional court, as interim president while preparations are made for special elections.

Deposed President Mohamed Morsi has been moved to an undisclosed location, according to one of his aides. Reports from the ground suggest that tensions between pro-Morsi and anti-Morsi protesters are high:

Egyptian President Mohamed Morsi is in the process of being overthrown in a military coup d'état, claims top Morsi adviser Essam al-Haddad in a new Facebook message.

"As I write these lines I am fully aware that these may be the last lines I get to post on this page," writes al-Haddad. "For the sake of Egypt and for historical accuracy, let’s call what is happening by its real name: Military coup."

Al-Haddad laments what he sees as a failure by opposition parties to respect the democratic process:

Let me be very clear. The protesters represent a wide spectrum of Egyptians and many of them have genuine, valid grievances. President Morsy’s approval rating is down ... In a democracy, there are simple consequences for the situation we see in Egypt: the President loses the next election or his party gets penalized in the upcoming parliamentary elections. Anything else is mob rule.

Many have seen fit in these last months to lecture us on how democracy is more than just the ballot box. That may indeed be true. But what is definitely true is that there is no democracy without the ballot box. [Facebook]

Morsi and his Muslim Brotherhood have remained defiant as a military-imposed deadline to strike a deal with opposition leaders passed. Critics have accused Morsi of ramming an Islamist constitution through parliament and failing to fix the economy.

Sources within the Egyptian military have stated that if no deal was reached, the military would suspend the constitution, dissolve the Muslim Brotherhood-led parliament, and hold new presidential and parliamentary elections.

The scene near Tahrir Square, packed with protesters, has been chaotic:

Images appear to show security forces dramatically ramping up their presence in Cairo:

And pro-Morsi protesters have clashed with military forces:

Morsi's opponents, however, see al-Haddad's statement as a cynical ploy to frame their movement as a power grab by the military.

More as this story develops.