Russia on Tuesday called for an "objective and impartial" U.N.-led probe into last week's massacre in the Syrian city of Houla that killed 108 people and left some 300 wounded.

"At this stage, there should be an objective and impartial investigation conducted under the auspices of the U.N. monitoring mission in Syria," the foreign ministry said in a statement after telephone talks between Foreign Minister Sergei Lavrov and international peace envoy Kofi Annan.

The long-overdue process of updating electoral lists in Gaza is expected to take six weeks, the head of the Palestinian Central Election Commission said on Tuesday.

The announcement was made a day after Hamas gave the CEC the green light to begin updating the lists for the first time in six years in a key step to paving the way for elections.

Syria's main opposition coalition called on Tuesday for a U.N. Security Council resolution authorizing the "use of force" and welcomed the expulsion of top diplomats from several Western countries.

After economic sanctions and the expulsion of top diplomats from several Western countries, the U.N. Security Council should "adopt a resolution under Chapter VII (of the U.N. Charter) allowing the use of necessary force in order to put a stop to the genocide and the murders committed by the regime's militias," the Syrian National Council said.

Egypt's Muslim Brotherhood presidential candidate Mohammed Mursi sought on Tuesday to reassure women and Coptic Christians, who fear a conservative Islamist could threaten their freedoms.

"Our Christian brothers, let's be clear, are national partners and have full rights like Muslims," said Mursi in a press conference.

Major Western powers said Tuesday they would expel Syria's diplomatic envoys in protest at the weekend massacre in the town of Houla, in which more than 100 people were killed.

The United States, Britain, France, Germany, Italy and Spain as well as Canada, Australia, The Netherlands, Bulgaria, Switzerland and Belgium announced decisions to expel ambassadors or top envoys.

Israeli President Shimon Peres said on Tuesday that Syrian President Bashar Assad has become the "murderer" of his people and they need help to free themselves from his regime.

"Their president, who is supposed to be the father of their nation, became their murderer," Peres told reporters during a joint press conference with visiting German President Joachim Gauck.

Saudi Arabia on Tuesday renewed a warning to its citizens not to visit Yemen, still reeling from a year of political unrest and an ongoing war against al-Qaida, the state news agency SPA said.

"Given the instability and the security situation" in Yemen, "the (foreign) ministry is renewing its warning to all citizens not to travel" there "until the situation is stabilized," an official said in a statement carried by SPA.

Most of the victims of the massacre in the Syrian town of Houla were summarily executed, the U.N. rights body said on Tuesday, amid global outrage over the killings.

"It's believed that under 20 of the 108 killings can be attributed to artillery and tank fire," said Rupert Colville, spokesman for the United Nations High Commissioner for Human Rights.

At least 19 people were killed in violence on Tuesday in Syria, where clashes between regime troops and rebels raged, monitors said.

In central Homs province, seven civilians were killed overnight, the Syrian Observatory for Human Rights said. Three of them died when the army shelled the outskirts of restive Qusayr, while four died in the city of Homs.

Five people have been killed in an assault launched by al-Qaida fighters Tuesday on a Yemeni army convoy ferrying supplies to troops in the restive southern Abyan province, a military official said.

Three Yemeni soldiers and two fighters of al-Qaida were killed during the assault on the military convoy in the village of Mazraat Mashhour, southwest of Zinjibar, the capital of Abyan, the official told Agence France Presse on condition of anonymity.