Judges in Egypt's appeal courts have called a strike in protest at President Mohammed Mursi's recent decree giving himself new powers.Appeals courts and the Court of Cassation will halt work until the decree is revoked, the judges say.The decree, issued last Thursday, gave Mr Mursi powers to take any measures to protect the revolution, and stated that no court could overturn his decisions.The move sparked anger and widespread protests.Mr Mursi's backers say the decree was needed to protect the gains of the revolution against a judiciary with deep ties to overthrown President Hosni Mubarak.The Muslim Brotherhood and other Islamist groups have called a rally for Saturday in support of Mr Mursi.On Monday, Mr Mursi sought to defuse the crisis by saying the decree granting him new powers was limited in scope.He met senior judges and told them that the measure would be restricted to "sovereign matters" designed to protect institutions.But judges who attended the meeting said they were not satisfied. They want him to withdraw the measure completely.Protesters who have taken to the streets since the decree was issued last Thursday say Mr Mursi's Muslim Brotherhood has hijacked the revolution.Anti-Mursi protests were held in Cairo, Alexandria, Suez, Minya and other Nile Delta cities on Tuesday.Low-level rallies continued in Cairo's Tahrir Square on Wednesday.The Brotherhood has organised counter-demonstrations.The decree bars judges from dissolving the assembly that is drawing up a new constitution.The president is also authorised to take any measures to preserve the revolution, national unity or safeguard national security.Critics say the decree is an attack on the judiciary.