Hamas' Gaza premier Ismail Haniya hailed on Friday the "heroic" Syrian struggle for democracy during a rally at Cairo's Al-Azhar mosque, in a departure from his movement’s refusal to criticize Damascus.

"I salute all the people of the Arab Spring, or rather the Islamic Winter," Haniya told several thousand cheering people who attended a rally in support of the Palestinians and Syrians.

At least 93 people were killed on Friday across Syria as regime forces shelled a rebel-held area of the city of Homs for the 21st straight day, while tens of thousands protested in several regions, monitors said.

The bombing targeted the district of Baba Amr, where hundreds have reportedly been killed since forces loyal to President Bashar al-Assad began an artillery attack on February 4, the Britain-based Syrian Observatory for Human Rights said.

Clashes broke out Friday between Israeli police and "hundreds" of Palestinian stone-throwers at the flashpoint al-Aqsa mosque compound in Jerusalem's Old City, police said.

"They threw stones towards the Maghrebi Gate and police went onto the plaza," police spokeswoman Luba Samri told Agence France Presse, referring to the only entrance to the compound which can be used by non-Muslims.

Al-Qaida's front group in Iraq said on Friday that it carried out a wave of bombing and shooting attacks across the country that killed 42 people.

The group said Thursday's attacks, which hit six different provinces and left more than 250 people wounded, targeted security forces in response to "torture and killings against Sunnis".

Dozens of Iraqis demonstrated for reforms in Baghdad's Tahrir Square on Friday, the eve of the first anniversary of mass protests in which 16 people were killed across the country.

Security forces had a heavy presence in the square, with soldiers armed with wooden clubs, pistols and assault rifles surrounding the area where the demonstrators were gathered.

New international mediator Kofi Annan urged all sides in the Syria crisis on Friday to cooperate with his mission, saying he was determined to put an end to the violence and human rights abuses.

"I look forward to having the full cooperation of all relevant parties and stakeholders in support of this united and determined effort by the United Nations and the Arab League to help bring an end to the violence and human rights abuses, and promote a peaceful solution to the Syrian crisis," he said.

Amnesty International demanded on Friday that aid agencies be given immediate access to Homs and other besieged Syrian protest cities, as world powers gathered in Tunisia to discuss the bloodshed.

The London-based human rights watchdog said it had received the names of 465 people reported killed in Homs since regime forces began pounding rebel neighborhoods of Syria's third-largest city three weeks ago.

A Syria-based opposition group said it was boycotting the international "Friends of Syria" meeting being held on Friday in Tunis on the future of the country, complaining of exclusion and fearing escalated militarization.

The National Coordination Committee for Democratic Change (NCCDC) denounced what it described as attempts to leave the door open to militarize the uprising against the regime of Bashar Assad, and for foreign military intervention.

French ambassador to Syria Eric Chevallier has returned to Damascus more than two weeks after being recalled in response to the Syrian government's crackdown on dissent, the embassy said on Friday.

"I can confirm that the ambassador of France returned to Damascus on Thursday night," a spokesman told Agence France Presse.

Israeli warplanes launched two air strikes on the Gaza Strip early Friday, the military said; hours after Palestinian militants fired two rockets at southern Israel.

"Israeli army aircraft thwarted an attempt by a terrorist squad to fire rockets at Israel from the northern Gaza Strip," an army statement said.