HONOLULU - US First Lady Michelle Obama surprised excited kids on Saturday by answering an air defense hotline set up to track Santa's Christmas Eve trek around the globe with his reindeer.

"Right now, I am looking at the tracker and I can see a dot on the satellite screen. It says that Santa, right now, is flying over Finland," Obama told a girl named Summer. She added that the sleigh was full of toys.

The first lady, on vacation with President Barack Obama and their daughters in Hawaii, volunteered for a second time in the annual NORAD Tracks Santa program, run by the North American Aerospace Defense Command.

Another girl, Victoria, asked her if the space-age tracking technology deployed by NORAD could decipher whether Rudolph was at the head of Santa's sleigh.

"There's a little flashing light on this tracker, and the experts think that it is probably Rudolph who's leading the sleigh this year. So he's out there," Obama said.

The first lady said during one of her 10 calls with kids that she had already got her Christmas gift, the arrival on Friday of her husband to join his family, after a tax standoff in the US Congress threatened to keep him in Washington.

"We were all praying and praying, and asking Santa, and the Tooth Fairy, and every fairy that they could think of - that's what Malia and Sasha were doing - that he would be able to be with us on Christmas."

NORAD's Santa tracking tradition, a break from the now deadly serious business of securing North American skies, dates back to 1955.

The air command - which monitors the skies over Canada and the United States - makes every effort to locate Saint Nick, using no less than four high-tech systems: radar, satellites, "Santa Cams" and even fighter jets.

Children and the young at heart can track the jolly man in the big red suit online at noradsanta.org, which shows a map of Santa's current location and provides constant updates in eight languages: English, French, Spanish, German, Italian, Japanese, Portuguese and Chinese.

NORAD said there had been over 60,000 calls already to the Santa line, and officials expect last year's record of 80,000 calls to be broken.

By midnight on Thursday according to the latest available figures, noradsanta.org had 7.6 million unique hits and the command's Santa page on Facebook had more than 961,000 "likes" - already a record.

A total of 1,200 volunteers staff the Santa operation center in Colorado Springs.

Earlier on Saturday, the president and first lady thanked US troops and their families for their sacrifice and service to the country as they wished all Americans happy Christmas holidays in a radio and Internet address.

"Our veterans, troops, and military families sacrifice so much for us," Michelle Obama said. "So this holiday season, let's make sure that all of them know just how much we appreciate everything they do."

Agence France-Presse