Morsy's account "urges everyone to adhere to peacefulness and avoid shedding blood of fellow countrymen."
[Updated at 3:37 p.m. ET, 9:37 p.m. in Egypt]
It's not all celebration in Cairo. Pro-Morsy demonstrators in Cairo are furious, CNN's Ben Wedeman reports from near their rally.
Thousands at the pro-Morsy rally chanted "down with military rule" and "invalid" upon listening to the military announcement of Morsy's ouster.
Morsy enjoyed support from the Muslim Brotherhood, the Islamist movement that propelled Morsy to the presidency. CNN's Fareed Zakaria said much will depend on whether and how the Muslim Brotherhood will challenge the army's move.
Morsy, a U.S.-educated religious conservative, was elected president in June 2012. But his approval ratings have plummeted. His government has failed to keep order as the economy has tanked and crime has soared, including open sexual assaults on women in Egypt's streets. Chaos has driven away many tourists and investors.
That has disaffected many among Egypt's poor and middle classes, Fawaz Gerges, director of the Middle East Center at the London School of Economics, told CNN this week.
"The millions of Egyptians who cheered for Morsy are saying he must go," Gerges said.
[Updated at 3:26 p.m. ET, 9:26 p.m. in Egypt]
Car horns are honking and fireworks are going off in Tahrir Square, the heart of the anti-Morsy protests that is still filled with thousands upon thousands of people.
CNN's Reza Sayah, who's at the square, described it as "an explosion of joy."
[Updated at 3:24 p.m. ET, 9:24 p.m. in Egypt]
Morsy's ouster comes hours after the passing of a deadline set by the military, which had told Morsy, in effect: Make a deal with the opposition and settle the unrest of the past few days, or be ousted.
The officer who announced the move moments ago, Gen. Abdel-Fatah El-SisiEl-Sisi, said the head of the country's constitutional court will serve as Egypt's temporary president until a new constitution can be drawn up and new elections can be held.
[Updated at 3:18 p.m. ET, 9:18 p.m. in Egypt]
CNN's Ivan Watson in Cairo said he had seen Egyptians celebrating the overthrow of Egypt's first democratically elected president.
"I am quite stunned by how much ill will he generated among so many Egyptians, that they throw away the electoral process and start again," he said.
[Updated at 3:13 p.m. ET, 9:13 p.m. in Egypt]
Egyptian President Mohamed Morsy, elected just a year ago, has been ousted from power, Gen. Abdel-Fatah El-Sisi just said in a televised address.
El-Sisi, Egypt's top military officer, announced that Morsy was no longer the leader of the country and warned the military would respond firmly to any violence. He also outlined a political road map for the country to follow.
Anti-Morsy demonstrators in Cairo's Tahrir Square, listening to the address, roared their approval when El-Sisi finished.
[Updated at 12:45 p.m. ET, 6:45 p.m. in Egypt]
Key statements from both sides are coming out on social media.
This from Essam al Haddad, Egypt's presidential senior adviser on foreign affairs, on his Facebook page:
"As I write these lines I am fully aware that these may be the last lines I get to post on this page. For the sake of Egypt and for historical accuracy, let's call what is happening by its real name: Military coup."