Kidnappers holding four Westerners have made no contact with Iraqi authorities, on the day which they had set as a deadline to kill the humanitarian activists unless US and Iraqi authorities release all prisoners they hold in Iraq, the interior ministry has said.

Insurgents killed four American soldiers in separate attacks Saturday as violence mounted five days ahead of national elections. U.S. officials announced the release of 238 detainees but said the move was unrelated to demands by kidnappers of four Christian peace activists to free all prisoners.

A Nigerian jetliner carrying 110 people, most of them schoolchildren heading home for Christmas, crashed in a lightning storm Saturday while landing in this delta oil port, and at least 103 people were killed, officials said.

Richard Pryor, the caustic yet perceptive actor-comedian who lived dangerously close to the edge both on stage and off, died Saturday. He was 65. Pryor died shortly before 8 a.m. of a heart attack after being taken to a hospital from his home in the San Fernando Valley, said his business manager, Karen Finch. He had been ill for years with multiple sclerosis, a degenerative disease of the nervous system.

A deadly accident in which a Boeing 737 slid off the end of a snowy runway brought renewed demands Friday for buffer zones or other safety measures at hundreds of airports around the nation to give pilots a wider margin for error. In Thursday night's tragedy at Midway Airport, a Southwest Airlines jet making a landing plowed through a fence and into a street, killing a 6-year-old boy in a car. Ten other people, most of them on the ground, were injured.

People in low-lying coastal areas of the southern Indian state of Tamil Nadu have been advised to move to shelters as a cyclone approaches the region. Cyclone Fanoos is moving west in the Bay of Bengal with wind speeds said to measure 60km (37 miles) per hour.

The government has been accused of covering up the sale of 20 tonnes of heavy water to Israel for its nuclear programme in the early 1950s. The BBC's Newsnight says fresh evidence shows the UK knew the ingredient it sold to Norway would be subsequently sold on to Israel for nuclear weapons.

The US military in Iraq has launched a formal investigation into a video that appears to show security contractors firing randomly at Iraqi civilians. The video appeared on a website reportedly run by a former employee of London-based Aegis Defence Services.

A member of the Hezbollah militant movement has escaped a bomb attack on his car in eastern Lebanon. The explosion happened in the Hezbollah stronghold of Baalbek, near the Syrian border, but caused no casualties, police have said. The Hezbollah official had got out of the car moments before the blast, reports have said.

Top UN human rights official Louise Arbour has repeated accusations made earlier this week that the US and other countries are easing curbs on torture. Ms Arbour told the BBC that governments had to clarify if they were holding prisoners in secret jails, without the freedom to communicate or be visited.