Syrian security forces shot dead at least 25 people while dispersing tens of thousands of demonstrators in the central city of Hama on Friday, activists said, as anti-regime protests spread to Damascus.

Activists in the city told Agence France Presse by telephone that dozens of other people were wounded.

Yemen's embattled President Ali Abdullah Saleh was wounded on Friday when dissidents shelled a mosque in the presidential compound, as Yemen teetered towards civil war and Washington urged a peaceful transition of power.

A leader of the ruling General People's Congress (GPC) party told Agence France Presse that Saleh was "lightly wounded in the back of his head."

Fighting that has killed scores of people in north Sanaa spread to the south on Friday when Yemeni troops shelled the home of Sheikh Hamid al-Ahmar, a leader of the biggest opposition party, witnesses said.

The attack with heavy weapons and missiles targeted the home of Sheikh Hamid, a brother of powerful tribal chief Sheikh Sadiq al-Ahmar, whose men have been locked in fierce clashes with loyalist security forces in the north of the capital, witnesses said.

A bomb placed outside a mosque frequented by provincial officials in the Iraqi city of Tikrit killed 17 people and wounded 50 after the main weekly Muslim prayers on Friday, a security official said.

Two members of the provincial council and a police officer were among the wounded, the official said.

Palestinian president Mahmud Abbas met Pope Benedict XVI on Friday amid heightened tensions across the Middle East and Vatican concern about the treatment of Christian minorities in the region.

This is the fourth time Benedict meets Abbas since becoming pope in 2005.

Israeli businessman Sammy Ofer, whose company Ofer Brothers is embroiled in a scandal over illegal trade with Iran, was found dead at his Tel Aviv home on Friday, media reports said. He was 89.

Ofer, a shipping magnate who was one of the founders of the Ofer Brothers Group, died early on Friday of a "serious illness," Israeli public radio said, without giving further details.

Russia Thursday warned Syria's opposition to President Bashar al-Assad against destabilizing the country and told the West not to provoke the situation for the sake of "regime change".

Syrian opposition groups were meeting in Turkey to discuss plans to support the revolt against Assad's regime, dismissing his calls for dialogue as a belated move.

At least three explosions near provincial government offices in the western Iraqi city of Ramadi killed 10 people and wounded 15 on Thursday evening, security officials said.

Two other officials said a fourth explosion took place in the city, 100 kilometers west of Baghdad, as emergency services rushed to treat casualties.

Syrian opposition groups called Thursday for President Bashar al-Assad's immediate resignation, in a joint declaration at the end of a two-day meeting in Turkey.

The statement, read out in Arabic in the Mediterranean resort of Antalya, urged the "immediate resignation of President Bashar al-Assad from all functions he occupies" and asked him to "leave his powers to a vice-president," without specifying whom it was referring to.

U.S. Secretary of State Hillary Clinton said Thursday that the international community needs to be more united on dealing with the Syrian government's crackdown on the pro-democracy movement there.

"Right now the attitude of the international community is not as united as we are seeking to make it," the chief U.S. diplomat told reporters.