Egypt crisis: Tahrir Square activists maintain pressure
Hundreds of Egyptian protesters are occupying Cairo's Tahrir Square in a effort to capitalise on popular anger following the trial of Hosni Mubarak.
There were mass protests on Saturday and overnight against what many see as lenient sentences handed down against the ex-president and security aides.
More than 100 people have been wounded in nationwide protests, officials say.
Egypt's prosecutor-general has lodged appeals against the sentences.
In a statement, the prosecutor's office said he had ordered "the start of the appeals procedure" but did not clarify whether he would appeal against all the verdicts, or just the acquittals.
The Muslim Brotherhood's presidential candidate toured the square and called for "the revolution to continue".
Mubarak and his former interior minister, Habib al-Adly, were jailed for life on Saturday for complicity in the killing of protesters during last year's uprising.
But six former police commanders were acquitted, and Mr Mubarak and his sons were cleared of corruption.
Correspondents say a verdict that was meant to bring closure for Egypt is in danger of reopening old wounds.
Thousands of protesters filled Tahrir Square, the focal point of the uprising that forced Mubarak from power.
Many chanted "down with the military rule" - the slogan of last year's revolution.
"The Mubarak verdict mocks us. He and [former Interior Minister Habib] Adly got a sentence and their aides got nothing," protester Sharif Ali told the BBC. "When they return to court on appeal, they will be freed too."
The Muslim Brotherhood's candidate in the country's presidential election, Mohammed Mursi, visited the square late on Saturday.
He later told reporters that, if elected, he would retry Mubarak and former regime officials suspected of involvement in killing protesters.
"The best guarantee to reach our goals is for the revolution to continue," Mr Mursi added.
After further protests overnight, some protesters stayed on Tahrir Square saying they were determined to stage a sit-in.
"We expect a lot more people to come during the day," activist Omar Abdelkader told AFP news agency on Sunday.
Another protester, Osama Awad, told Reuters: "Yesterday people were united like in the early days of the revolution. I felt the revolution is returning."
Campaign HQ stormed
The BBC's Yolande Knell in Cairo says many poured on to the streets out of depression at the current political situation.
The first round of recent presidential elections has left Egyptians with a choice between Mr Mursi, an Islamist, and Ahmed Shafiq, Mubarak's last prime minister.
In a separate development, protesters stormed Mr Shafiq's campaign headquarters south of Cairo.
Mubarak, 84, is the first former leader to be tried in person since the start of the Arab Spring in early 2011.
Announcing the verdicts, Judge Ahmed Refaat said Mubarak and Adly had failed to stop security forces using deadly force against unarmed demonstrators.
Mubarak and his two sons, Alaa and Gamal, were acquitted on separate charges of corruption.
But his sons will remain in detention as they are to be charged with stock-market manipulation.
Mubarak, who ruled the country from 1981 to 2011, had faced a possible death sentence over the killing of about 850 protesters.
The first leader toppled during the Arab Spring was Zine al-Abidine Ben Ali of Tunisia, who was found guilty in absentia of drugs and gun charges in July.
Libyan leader Muammar Gaddafi was killed by rebels in October. Yemen's Ali Abdullah Saleh received immunity from prosecution after handing over power in November.