The court officers were gunned down hours after Morsi was condemned to die by a Cairo judge, along with about 100 fellow Muslim Brotherhood supporters.

The sentence was denounced by Turkish President Recep Tayyip Erdogan and if carried out could make Morsi, a boss of the brothers who became Egypt’s first freely elected leader, a martyr to Islamists worldwide.

The attack took place in the provincial capital of El-Arish in the Sinai, where security forces are locked in a bloody struggle with an offshoot of Islamic State.

A driver and second prosecutor were wounded when gunmen opened fire, killing the three ­judicial officials as they were being driven to court. There was no claim of responsibility for the ­attack, but it was consistent with warnings of a backlash against Mr Morsi’s sentencing.

Dressed in blue prison overalls, the former president had stood inside a metal and glass cage as the death verdict was pronounced on Saturday.

He was convicted for fleeing prison at the height the 2011 “Arab spring’’ revolt against then president Hosni Mubarak, having been detained with other Muslim Brotherhood leaders and figures in the protest movement. Morsi overreached in office and he was overthrown in a 2013 coup led by then general Abdel Fattah el-Sisi, who supplanted him as president.

The death sentence must be ratified by Egypt’s ranking Islamic figure, the Grand Mufti, and can be appealed through the courts. However, further charges are pending over alleged fraud, insulting the judiciary and leaking documents. On top of this, Morsi was sentenced to 20 years’ jail last month for inciting violence and overseeing the torture of prisoners while president.

The charges have been rejected by the Muslim Brotherhood, which was driven underground after being banned by Mr Sisi, loading the legal trap that ­ensnared Australian journalist Peter Greste and two colleagues from the Al Jazeera English news service.

Mr Erdogan called the death sentence a return to “ancient Egypt’’ and was scathing of Western nations for failing to support Morsi as an elected leader.

The US expressed its “deep concern”, with a State Department official saying: “We have consistently spoken out against the practice of mass trials and sentences, which are conducted in a manner that is inconsistent with Egypt’s international obligations and the rule of law.”

Morsi and his co-accused were convicted en-masse of conspiring with Hamas, the Brotherhood’s Palestinian arm, to carry out the illegal jailbreak in January 2011 even though they would have been in danger of their lives from Mubarak’s brutal security services.