Tens of thousands of people on Saturday filled an avenue in Moscow to protest against the alleged rigging of parliamentary polls, in a new challenge to Russian strongman Vladimir Putin's authority.

Clutching white balloons and banners with the slogan "For Free Elections", the protestors thronged Sakharov Avenue in Moscow, symbolically named after the Nobel-winning dissident Andrei Sakharov who for years defied the USSR.

A wave of attacks in northern Nigeria attributed to a radical Islamist group may have killed up to 100 people, police and a local rights group said Saturday.

"From reports I have been receiving from Damaturu, up to 100 people could have been killed," a senior police source in the region told Agence France Presse, while Chidi Odinkalu, head of the Open Society Justice Initiative, gave a figure of 69-100.

Real estate mogul and reality TV personality Donald Trump has quit the Republican Party to register as an independent, opening the way for a potential outsider run at the White House, reports said Friday.

Trump made the switch on Thursday, his lawyer, Michael Cohen, told The Hill political news website.

An explosion at a coal mine in northern Afghanistan has killed 11 people, an official said Saturday.

The miners, who were all working at the site without government permission, died after an explosion triggered a collapse at the mine in Baghlan province on Friday night, said the provincial governor's spokesman Mahmood Haqmal.

President Raul Castro on Friday put on ice highly-anticipated plans to ease travel restrictions on Cubans, telling lawmakers the nation would not be pressured into moving too fast and citing continued aggression from the United States as the reason for his cautious approach.

Cuba has been awash in speculation the much-hated regulations, which prevent most Cubans from leaving the island, might be lifted during Friday's session of the National Assembly. But Castro said the time still wasn't right, despite a year of free-market reforms that has seen the Communist government legalize a real estate market and greatly increase private business ownership.

The Duke of Edinburgh, the 90-year-old husband of Britain's Queen Elizabeth II, is recovering in hospital after successful heart surgery Friday for a blocked coronary artery, Buckingham Palace said.

The duke, also known as Prince Philip, underwent an "invasive procedure of coronary stenting" after being rushed to hospital with chest pains, the palace confirmed.

A suicide car bomb attack in northwest Pakistan killed six soldiers and wounded about a dozen others on Saturday, police said.

The attack took place in Bannu city where the bomber targeted the camp office of the paramilitary Frontier Corps troops, who are deployed in militant-infested North Waziristan, which borders Afghanistan.

The U.S. Central Intelligence Agency has suspended drone missile strikes on gatherings of low-ranking militants in Pakistan due to tensions with that country, The Los Angeles Times reported.

Citing unnamed current and former U.S. officials, the newspaper said late Friday the undeclared halt in CIA attacks is aimed at reversing a sharp erosion of trust between the two countries.

Pakistan's top judge on Friday ruled out any possibility of a military coup as the Supreme Court deliberated a scandal that has significantly escalated tensions between the government and the military.

"Rest assured... in this country there is no question of (military) takeover because the people trust the apex court now," said Iftikhar Muhammad Chaudhry, while hearing petitions calling for an investigation into the scandal.

Police on Friday fired tear gas at hundreds of people and detained a team of Hong Kong journalists in a southern Chinese town that was the scene of violent protests earlier this week.

Television footage from Hong Kong broadcaster Cable TV showed police in full riot gear fire gas canisters towards a crowd of residents gathered on a main highway, who covered their faces and fled.