* Wide rift between Mursi government and judges over reform
* Changes would force more than 3,000 judges to retire
* Men throw petrol bombs at president's palace, car set alight
Egypt's Islamist-dominated parliament must move quickly to adopt judicial reforms that have sparked a revolt by judges, the deputy leader of the Muslim Brotherhood's political arm argued on Friday.
The proposed reforms, which would get rid of more than 3,000 judges by lowering the retirement age, have widened the rift between President Mohamed Mursi's government and a judiciary seen by its critics as a last bastion of the old regime that was toppled in the 2011 revolution.
Essam el-Erian, a member of parliament from the Freedom and Justice Party which dominates the legislature, said in a Facebook post that passage of a new law defining the powers of the judiciary should not be delayed.
He said the upper house had the legal authority to do this - something the opposition disputes. The lower chamber was dissolved by court ruling last year and Mursi has said new elections could be held in October.
More than two years after the uprising that ousted President Hosni Mubarak, Egypt is still beset by political turmoil and street violence has contributed to a severe economic crisis by scaring off tourists and foreign investors.
Dozens of masked young men threw petrol bombs and stones in an attempt to break into Mursi's palace in Cairo late on Friday, state news agency MENA reported.
It said members of the black-clad anti-government group known as the Black Bloc were present but that the police fired tear gas to force the small group to disperse. A car was set on fire outside the palace, footage from satellite news channel Al Jazeera's Egypt station showed.
A heavy police presence reinforced the palace's perimeter after nightfall. The police used trucks to block off streets near the palace, preventing protesters from approaching.
Twelve people were arrested on Friday night in connection with the clashes, MENA reported, citing an unnamed security source.
Outside the High Court, which was the scene of clashes last week between Islamist protesters and their opponents, a small crowd of demonstrators gathered earlier on Friday to chant for the judiciary's independence. Islamist parties postponed their latest round of protests calling for it to be purged.
A senior official of Egypt's biggest hardline Islamist party on Friday rejected the reforms under consideration. Abdullah Badran of the Nour Party wrote on Facebook that the constitution required greater consultation with the judiciary.
Separately, a judge who served as the head of the embattled constitution-drafting body said reforms should be postponed until after a new parliament is elected, MENA reported.