Egyptian President Mohammed Mursi
Egyptian President Mohammed Mursi has said his move to order the retirement of two of the country's top generals was for "the benefit of this nation".
He was speaking after replacing the powerful head of the armed forces, Field Marshal Mohamad Hussein Tantawi, and Chief of staff Sami Annan.
According to the BBC, Mursi also said a constitutional declaration aimed at curbing presidential powers had been cancelled.
Mursi, who was elected in June, is a member of the Muslim Brotherhood.
Relations between Islamists and the military have been increasingly tense since the fall of President Hosni Mubarak last year amid mass street protests.
"The decisions I took today were not meant ever to target certain persons, nor did I intend to embarrass institutions, nor was my aim to narrow freedoms," Mursi said during a speech to mark the Muslim fasting month of Ramadan.
"I did not mean to send a negative message about anyone, but my aim was the benefit of this nation and its people," he said.
The president also praised the armed forces, saying they would now focus "on the holy mission of protecting the nation".
It was announced earlier that a career army officer, Gen Abdel-Fattah al-Sisi, would replace Field Marshal Tantawi as both armed forces chief and defence minister.
Field Marshal Tantawi, 76, has not yet indicated whether he accepts the moves.
However Gen Mohamed el-Assar, a member of the Supreme Council of the Armed Forces (SCAF), told Reuters news agency the decision had been "based on consultation with the field marshal, and the rest of the military council".
A presidential spokesman said Gen Annan and Field Marshal Tantawi had been appointed as presidential advisers and were given Egypt's highest state honour, the Grand Collar of the Nile.
BBC Middle East correspondent Kevin Connolly says the dismissal of senior military officers will be seen by Egyptians as a decisive move in a struggle for real power between the country's newly elected politicians and the generals who have exercised power for many years.
As head of SCAF, Field Marshal Tantawi became Egypt's interim ruler after President Mubarak was ousted following last year's mass protests.
Under the interim constitutional declaration issued by Scaf before Mursi was sworn in, the president could not rule on matters related to the military - including appointing its leaders.
Meanwhile, a group of armed men shot dead a tribal leader and his son on Monday in Egypt's Sinai peninsula on the border with Israel, a security source said, as violence escalated on the sixth day of a military crackdown on militants in the area.
"Tribal leader Khalaf Al-Menahy and his son were shot dead by militants on their way back from a conference organized by tribal leaders to denounce militancy," said the security source in Sinai.