"A greeting from the heart filled with love, appreciation and respect to our leaders who passed on the banner. They will be in our eyes and hearts," said the posting. "The armed forces is a prestigious institution with a doctrine of full discipline and commitment to legitimacy."
Egypt's official news agency quoted an unnamed military official late Sunday as saying there has been no "negative reaction" from within the military. And a day after the orders, no unusual military movements were detected anywhere across the nation.
The United States, Egypt's main foreign backer of 30 years, said it was unperturbed by the changes. Egypt receives about $1.5 billion in annual U.S. aid.
"We had expected President Morsi at some point to coordinate changes in the military leadership to name a new team," U.S. Defense Department press secretary George Little said in Washington. "The United States and the Department of Defense in particular look forward to continuing the very close relationship with the SCAF [the Supreme Council of the Armed Forces]."
Morsi's moves could heighten fears in Egypt and abroad that the U.S.-educated Islamist leader may have accumulated too much power in his hands and those of the Muslim Brotherhood, his fundamentalist group.
"With [the] military stripped of legislative authority and in [the] absence of parliament, [the] president holds imperial powers," Egypt's top reform leader and Nobel Peace laureate Mohamed ElBaradei wrote on his Twitter account on Monday.
The Brotherhood won both parliamentary and presidential elections in the first free and fair votes in Egypt's modern history following Hosni Mubarak's ousting in a popular uprising last year. The group had been repressed under Mubarak, who ran a secular state. The military rulers who took power from Mubarak dissolved the Brotherhood-dominated parliament in June after a court ruled that a third of its members were illegally elected.
Some are anxious that Egypt is moving from an authoritarian state to an Islamic state. Others see what they describe as tell-tale signs of another authoritarian regime in the making.
The Brotherhood-dominated upper house of parliament, which was not dissolved, last week replaced many of the editors of 50 state-owned publications with journalists known to be sympathetic to the group.
Also last week, authorities shut down an independent television station whose owner and chief presenter, Tawfik Okasha, has gained popularity for his on-air rants against Morsi. Last week, he called for Morsi to be killed. On Monday, Egypt's top prosecutor referred Okasha along with the editor of an independent daily newspaper to a criminal court for trial on charges of incitement.
Last week, a crowd of suspected Brotherhood supporters stormed a TV complex in a suburb west of Cairo, attacking journalists and smashing cars to punish media critics of Morsi.
Following a series of recent attacks on Brotherhood offices, the group has vowed to protect its headquarters against possible violence during anti-Morsi protests scheduled for Aug. 24 in Cairo. The vow was seen by critics as an acknowledgment by the Brotherhood that it would resort to violence in the face of threats.
Analysts have floated the possibility that the shake-up of the military brass was part of a "safe exit" deal struck between Morsi and the generals to shield them against prosecution for alleged crimes during the time they ruled the country. They cite the appointment of Field Marshal Hussein Tantawi, the outgoing defense minister, and Gen. Sami Annan, the chief of staff, as presidential advisers as evidence to support their theory.
Three top generals retired by Morsi the chiefs of the air force, air defense and the navy were given senior government jobs.
If Morsi's decisions go unchallenged, it should end the power struggle that pitted him against the powerful military. That could mean the ushering out of six decades of de facto military rule since army officers seized power in a coup in 1952. But removing the defense minister and chief of staff does not necessarily mean that the military, Egypt's most powerful institution, has been defeated or that it would give up decades of perks and prestige without a fight.
Morsi has been locked in a power struggle with the military since he took office on June 30. But after militants killed 16 Egyptian soldiers a week ago at a border post with Israel in Sinai, he has sought more aggressively to assert his authority over the top generals.
He fired the nation's intelligence chief a few days after the Sinai attack and made two highly publicized visits to Sinai in the company of top commanders. He also chaired several meetings with the military leadership and made a point of calling himself the supreme commander of the armed forces in televised speeches.
On Sunday, he ordered the retirement of Tantawi, the defense minister, and Annan, the chief of staff. By appointing them as presidential advisers and awarding them some of the nation's highest honors it suggested they agreed, perhaps grudgingly, in advance.
The Supreme Council of the Armed Forces, which ruled Egypt for 17 months after Mubarak was forced out, stripped the presidency of many of its key powers before it handed the office to Morsi. Tantawi was the head of the SCAF and Annan was No. 2. Tantawi was also Mubarak's defense minister for two decades before the regime was ousted.
Days before Morsi's inauguration, the SCAF decreed constitutional amendments that gave them the power to legislate after they dissolved parliament, as well as control over the national budget. It also gave them control over the process of drafting a new constitution. The generals had put themselves in charge of all defense and foreign policy, including the appointment of the defense minister.
With his latest move, Morsi reclaimed the powers taken from him, seizing back sole control of the constitution drafting process, the national budget and the right to issue laws.
The two men appointed to replace the top military commanders were also members of the SCAF something that could indicate either the military's agreement to the shuffle or splits at the highest level of the armed forces. Lt. Gen. Abdel-Fattah el-Sissi replaced Tantawi and Lt. Gen. Sidki Sayed Ahmed replaced Annan.
Morsi may have tapped into divisions and the generation gap within the top echelons of the military. Tantawi is 76 and he was in that job for more than 20 years. His replacement, former military intelligence El-Sissi, is 58.
Egypt's first civilian president acted at a moment when the military was humiliated over a major security failure in Sinai. Several days before the killings, Israel warned that an attack was imminent. The intelligence chief was sacked after it emerged in Egyptian media that he knew of the Israeli warning but did not act.
Sinai has been plunged into lawlessness and the rest of the country has seen a sharp deterioration in security while the military ruled following Mubarak's ouster.
The military has a vast economic empire that accounts for about 25 percent of GDP. But it was tainted in the 17 months the SCAF ran the country, accused of mismanaging the transitional period and committing human rights violations.