By Hamid Ould Ahmed
ALGIERS (Reuters) - French warplanes and U.N. helicopters scoured the north of Mali on Thursday for the wreckage of an Air Algerie flight after it crashed carrying 110 passengers, nearly half of them French, from Burkina Faso to Algiers.
French Foreign Minister Laurent Fabius said authorities believed flight AH5017 may have encountered bad weather after the pilot requested to change direction shortly after takeoff due to a storm. However, he said no hypothesis had been excluded.
Officials in Mali and Burkina Faso gave conflicting accounts of locating the crash.
Malian President Ibrahim Boubacar Keita said wreckage of the flight had been spotted in his country's far north, toward the Algerian border between the towns of Aguelhoc and Kidal.
However, General Gilbert Diendere, a member of the crisis unit in Burkina Faso, said his team had found remains in southern Mali, 50 km (30 miles) from the Burkinabe border. Local authorities in the nearby town of Gossi also told Reuters the wreckage had been located here.
In Paris, Fabius said the flight, carrying 51 French nationals, had probably crashed but he said two French Mirage warplanes searching the vast desert area around the northern Malian city of Gao had spotted no wreckage.
"Despite intensive search efforts, no trace of the aircraft has yet been found," Fabius told journalists.
An Algerian official, who asked not to be identified, confirmed the flight had crashed but provided no other details.
French President Francois Hollande cancelled a planned visit to overseas territories and said France -- which has some 1,700 troops stationed in Mali -- would use all military means on the ground to locate the aircraft.
"The search will take as long as needed," Hollande told reporters. "Everything must be done to find this plane. We cannot identify the causes of what happened."
The searchers mission is complicated by the vast scale and daunting terrain of Mali. The area where the flight is suspected to have crashed is a sparsely inhabited region of scrubland and desert dunes stretching to the foothills of the Adrar des Ifoghas mountains.
Much of it lies in the hands of Tuareg separatist rebels, who rose up against the government in early 2012, triggering an Islamist revolt that briefly seized control of northern Mali.
The Malian government has only a weak presence in the region and relies on French and U.N. peacekeepers for aircraft and logistical support.
Another plane crash is likely to add to nerves over flying after a Malaysia Airlines plane was downed over Ukraine last week, a TransAsia Airways crashed off Taiwan during a thunderstorm on Wednesday and airlines temporarily cancelled flights into Tel Aviv due to the conflict in Gaza.
FRENCH PASSENGERS Algeria's state news agency APS said authorities lost contact with flight AH5017 an hour after it took off from Burkina Faso, but other officials gave differing accounts of the times of contact.
Swiftair, the private Spanish company that owns the plane, confirmed it had lost contact with the MD-83 operated by Air Algerie, which it said was carrying 110 passengers and six crew.
A spokeswoman for SEPLA, Spain's pilots union, said the six crew were from Spain. She could not give any further details.
It said it took off from Burkina Faso at 0117 GMT and was due to land at 0510 GMT but never reached its destination.
An Algerian aviation official said the last contact Algerian authorities had with the missing Air Algerie aircraft was at 0155 GMT when it was flying over Gao, Mali. Burkina Faso officials said the flight asked the control center in Niamey, Niger, to change route at 0138 GMT because of a storm in the Sahara.
Burkina Faso authorities said the passenger list comprised 27 Burkinabe, 51 French, eight Lebanese, six Algerians, two from Luxembourg, five Canadians, four Germans, one Cameroonian, one Belgian, one Egyptian, one Ukranian, one Swiss, one Nigerian and one Malian.
The Lebanese Foreign Ministry said its embassy in Abidjan estimated the number of Lebanese citizens on the flight was at least 20. Some of these may have dual nationality.
"We don't know anything yet. We have just heard from the news that the plane went missing," said Amina Daher, whose sister-in-line Randa was traveling on the plane with her three children, returning to Beirut to celebrate the Muslim religious festival of Eid El-Fitr with her family.
RELATIVELY CLEAN RECORD
The MD-83 is part of the McDonnell Douglas MD-80 family of twin-engined jets that entered service in 1980. A total of 265 of the MD-83 model were delivered before McDonnell Douglas, by then part of Boeing, halted production in 1999.
"Boeing is aware of the report. We are awaiting additional information," a spokesman for the U.S. planemaker said.
According to the Ascend Fleets database held by British-based Flightglobal, there are 187 MD-83s still in operation, of which 80 percent are being flown in the United States.
The aircraft's two engines are made by Pratt & Whitney, a unit of United Technologies.
Swiftair has a relatively clean safety record, with five accidents since 1977, two of which caused a total of eight deaths, according to the Washington-based Flight Safety Foundation.
Air Algerie's last major accident was in 2003 when one of its planes crashed shortly after take-off from the southern city of Tamanrasset, killing 102 people. In February this year, 77 people died when an Algerian military transport plane crashed into a mountain in eastern Algeria.
(Additional reporting by Patrick Markey, Daniel Flynn, David Lewis, Mathieu Bonkoungou, Emma Farge, Julien Toyer, Tracy Rucinski, Laila Bassam, Marine Pennetier, John Irish and Tim Hepher; Writing by Patrick Markey; Editing by Alison Williams and Sonya Hepinstall)