The U.N. Security Council struggled Tuesday through negotiations on how to respond to the Syria crisis that Russia's envoy warned was veering toward civil war.

Divisions remained among the 15 nations on the wording of any condemnation of President Bashar Assad's crackdown on protests and whether it should be a formal resolution or a less weighty statement.

Months after an uprising ended his 30-year-rule, Egypt's ex-president Hosni Mubarak faced trial Wednesday on murder charges, in a historic moment for the Arab region whose leaders are rarely held to account.

Mubarak, looking pale and dressed in white, appeared on a stretcher inside a cage at the courtroom set up in the Cairo Police Academy, as his two sons stood by his side in the dock.

Syrian dissidents on Tuesday urged U.S. President Barack Obama to call on Syrian leader Bashar al-Assad to quit power and to press for U.N. sanctions over his regime's deadly crackdown on protests.

The demands -- presented in a first meeting between U.S. Secretary Clinton and members of Syria's disparate opposition -- added to U.S. domestic pressure on the Obama administration to take a tougher line against Assad's regime.

The U.N. Security Council began a second day of talks on Syria Tuesday after President Bashar al-Assad's tanks shelled the protest hub of Hama on the opening day of the Muslim holy month of Ramadan.

At least 24 civilians were reported killed across the country on Monday, among them 10 during protests after special evening prayers, Syrian Observatory for Human Rights chief Rami Abdul Rahman said.

At least five people were killed on Tuesday as the Syrian army pressed on with its crackdown on the flashpoint protest city of Hama and troops stormed a Damascus suburb.

At least 24 civilians were reported killed across Syria on Monday, among them 10 during protests after special evening prayers, Syrian Observatory for Human Rights chief Rami Abdul Rahman said.

Libya's rebels said on Tuesday they launched a post-dawn attack on the western town of Zliten, punching through to the center and sparking fierce clashes with forces loyal to Moammar Gadhafi, as Russia said the fighting in Libya had reached a "dead end."

"The rebels advanced today inside Zliten to control the center. Now there is a vicious fight with Gadhafi's forces," said Colonel Ahmed Omar Bani, a military spokesman based in the rebel stronghold of Benghazi.

The European Union ambassador to Syria is to remain in Damascus despite an Italian proposal Tuesday to recall all ambassadors from the 27 EU nations.

"Our ambassador will remain in Damascus to observe what's happening on the ground," said Michael Mann, spokesman for EU foreign policy chief Catherine Ashton.

The Israeli secret service Mossad was responsible for the assassination last month of an Iranian scientist in Tehran, Germany's Spiegel Online news website reported.

The killing of Dariush Rezaei-Nejad was "the first serious action taken by the new Mossad chief Tamir Pardo," according to an unidentified Israeli intelligence source quoted by Spiegel Online.

Italy has recalled its ambassador in Syria for consultation given the "horrible repression against the civilian population," the foreign ministry said on Tuesday.

"The Foreign Minister Franco Frattini has given instructions for our ambassador in Damascus, Achille Amerio, to return to Italy for consultations," the ministry said in a statement.

The European Union on Tuesday added Syrian Defense Minister Ali Habib Mahmoud and four others to its blacklist of individuals and businesses associated with the ongoing repression there.

The EU's official journal also showed that the extended lists includes Mohammed Moufleh, head of Syrian military intelligence in Hama, the scene of a bloody crackdown by the army which activists say has left more than 100 dead.