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.

Australia Tuesday expelled Syria's top diplomat over the "hideous and brutal" massacre at Houla of more than 100 people, with Foreign Minister Bob Carr saying he expected other countries to follow suit.

Syrian charge d'affaires Jawdat Ali was notified of the decision to expel him and one other diplomat a day after he was called in to meet with officials over the killings which sparked global condemnation.

U.N.-Arab League peace envoy Kofi Annan urged Syrian President Bashar Assad to "act now" to end 15 months of bloodshed, during a meeting in Damascus on Tuesday.

"I appealed to him for bold steps now -- not tomorrow, now -- to create momentum for the implementation of the plan," Annan told reporters in the Syrian capital.

Iran announced Tuesday it has delayed the launch of an experimental observation satellite that was supposed to have happened a week ago, saying it would now take place sometime within the next 10 months.

The country's space agency chief, Hamid Fazeli, announced the new window for launch to the official Islamic Republic News Agency (IRNA).