Clashes between the army and Tuareg rebels in northern Mali have forced 172,000 people to flee their homes since mid-January, the United Nations humanitarian office (OCHA) said Thursday.

"The number of people displaced by the conflict reached more than 172,000 at the beginning of March, including more than 90,000 who have fled abroad, mostly to Mauritania, Burkina Faso and Niger," read a statement from the agency.

Gutsy "American Idol" contestant Jessica Sanchez took on Whitney Houston's biggest hit, delivering a performance that awed the show's judges.

When host Ryan Seacrest asked the panel to name Wednesday night's top two singers among the 13 finalists, Steven Tyler was ready.

Britain's defense secretary insisted on Thursday that the country's troops are committed to their mission in Afghanistan, after the number of U.K. personnel killed in the conflict passed 400.

Ministers have expressed fears that the deaths of six soldiers killed when an explosion hit their armored vehicle in the southwestern Helmand province on Tuesday evening would prompt new concern over the 11-year-long campaign.

Darting down the bumpy streets of Gaza wearing a cheap pair of sneakers, Palestinian runner Bahaa al-Farra dodges potholes and traffic as he trains to compete against the world's best athletes at the London Olympics.

Although an Olympic medal is a near impossibility, the 400-meter runner takes to the city streets for about three hours a day, speeding down crowded avenues in the morning before hitting the gym in the afternoon.

More work needs to be done to keep young Americans from using tobacco, including creating smoking bans and increasing taxes on tobacco products to deter youth, the U.S. Surgeon General's office said in a report released Thursday.

The report said it's particularly important to stop young people from using tobacco because those who start smoking as teenagers can increase their chances of long-term addiction. They also quickly can develop reduced lung function, early heart disease and other health problems.

Flying in formation around the moon, a pair of NASA probes began mapping the lunar gravity field in hopes of figuring out why Earth's only natural satellite is shaped the way it is.

The probes kicked off their science campaign late Tuesday two months after arriving back-to-back at the moon over the New Year's weekend.

Dogs seem to be as popular on a canvas these days as they are on a leash, with paintings of dogs drawing big bucks and big crowds.

At the annual "dogs only" art auction held after the Westminster Dog Show, two price records were broken this year, said Alan Fausel, vice president and director of fine art at Bonhams, the auction house that runs the event.

Arsenal fell one goal short of forcing extra time against AC Milan in the Champions League, going down 4-3 on aggregate in the last 16 despite winning 3-0 in the second leg on Tuesday.

Milan, seven-time winners, advanced to the quarterfinals for the first time since winning the title in 2007. Milan crushed the Gunners 4-0 in the first leg at the San Siro on February 15.

Rescuers shoveled through deep snow Wednesday searching for victims of an avalanche that destroyed a village of 200 people in northeastern Afghanistan, authorities said. Forty-seven people have been confirmed dead.

"We hope that some people were inside their homes and are still alive," said Shams Ul Rahman, the deputy governor of Badakhshan province, where the avalanche occurred on Sunday night. "But if the snow was too heavy, they may all be dead."

Call it McWashington.

A Nebraska woman has sold a three-year-old McDonald's Chicken McNugget that resembles President George Washington for $8,100 on eBay.