Syrian troops killed at least 23 people Friday when demonstrators took to the streets denouncing "despots and tyrants," as world powers cast doubt on the regime's commitment to an Arab peace deal.

Troops raked several residential neighborhoods of Homs -- a city of some one million people that has been at the frontline of protests raging since mid-March -- with heavy machineguns mounted on tanks, a watchdog said.

More than 2.5 million Muslim pilgrims began on Friday the rites of the annual hajj pilgrimage, leaving the holy city of Mecca for Mount Arafat, where the prophet Mohammed is believed to have delivered his final hajj sermon.

Dressed in white, they flooded the streets as they headed towards Mina, around five kilometers east of the holy mosque.

A U.S. soldier has been killed in northern Iraq, the U.S. military said on Friday, the first American service member to die in an attack here since the U.S. announced its forces would depart by year's end.

"A U.S. service member was killed Thursday while conducting operations in northern Iraq," the military said in a brief statement, without providing further details.

Embattled Australian carrier Qantas on Friday diverted one of its A380s to Dubai because of engine problems; a year to the day after a turbine blast in another of its superjumbos rocked the airline.

QF31 was four hours into the flight from Singapore to London, carrying 258 passengers and 25 crew, when the pilot decided that the oil pressure in one engine made it "absolutely important" to change course, a spokeswoman said.

Eleven people, including two children, have been killed in flash floods caused by heavy rains that have hit Oman over the past three days, the Arabian Peninsula state's police announced on Thursday.

"Eleven people died in several of the sultanate's provinces when their vehicles were swept by heavy rains as they drove through valleys," state news agency ONA quoted a police statement as saying.

Irish activists supporting a new bid to break Israel's blockade of the Gaza Strip urged their government on Thursday to seek Israeli assurances that a new aid flotilla would be allowed free passage.

The two vessels, the Irish Saoirse (meaning Freedom) and the Canadian Tahrir (Liberation in Arabic) which are carrying 27 people, are south-west of Cyprus and expect to reach Gaza by Friday, the activists told a press conference in Dublin.

Human rights groups on Thursday criticized the United Arab Emirates' trial of five activists accused of insulting top officials as "grossly unfair."

The trial of the five accused of "publicly insulting" the officials "has been grossly unfair, and the case against them has no basis in international law as it violates their freedom of expression," said a statement by a coalition of international human rights organizations.

A member of Yemen's consultative council and an army colonel were wounded on Thursday when their car was fired on by presumed al-Qaida militants, tribal sources said.

"Militants, suspected of belonging to al-Qaida, opened fire with a barrage of bullets at the car of Mohammed al-Haithami Ashal as he was heading towards Sanaa, wounding him in the leg," said a source from the Ashal tribe.

The elderly father of the second in command of Bahrain's largest Shiite opposition group Al-Wefaq died of his injuries on Thursday after riot police attacked him a day earlier, the organization said.

"Ali Hassan al-Dehi, 70, was attacked by riot police forces Wednesday evening" and died early Thursday, Al-Wefaq's website reported.

EU foreign policy chief Catherine Ashton urged Syria on Thursday to implement "fully and rapidly" an Arab League plan to end months of bloodshed.

"I welcome the efforts of the Arab League to end violence and bring about the reforms that the Syrian people have bravely demanded these last seven months," she said in a statement.