By Christopher Bjork, Robert Wall and Stacy Meichtry 

Air Algérie lost contact with Flight 5017 after takeoff from Ouagadougou, Burkina Faso, as the jetliner headed to Algiers with 116 people on board, Algeria's state news agency and the plane's operator said Thursday.

French Secretary of Transport Frédéric Cuvillier told reporters the plane disappeared over Northern Mali, where Islamist militants are fighting the Malian government and French forces. Numerous French nationals were aboard the missing plane, Mr. Cuvillier said.

Contact with the Boeing Co. MD-83, carrying 110 passengers and six crew members, was lost at about 1:55 a.m. local time, 50 minutes after the jet had taken off, the Algerian government's official news agency said in a statement. "Air Algérie launched [an] emergency plan," the agency added. It gave no other details.

An official at the directorate of Ouagadougou Airport said there had been an incident, "but for the moment we don't know anything more." He refused to give his name because he wasn't authorized to speak to reporters.

The missing plane has triggered a second global scramble among aviation regulators and safety officials in as many weeks, following the downing last week of Malaysia Airlines Flight 17 over war-torn eastern Ukraine.

It also follows a temporary flight ban imposed by the U.S. Federal Aviation Administration on American carriers using Tel Aviv airport, after a Hamas-fired rocket landed nearby earlier this week. The ban was lifted late Wednesday.

On Wednesday, forty-eight people died and 10 were injured after a TransAsia Airways plane went down in the outlying Penghu islands, off the coast of Taiwan.

The flight path of the missing Algerian jet isn't yet clear. The FAA has warned airlines to be extra vigilant when flying over Mali.

There is no indication the jet was shot down and no confirmation of a crash.

Still, amid questions by airline executives and regulators over whether MH17 should have been flying over eastern Ukraine, the Air Algérie jet's flight path will be closely scrutinized.

The FAA has banned U.S. carriers of flying over Mali at lower altitudes. The FAA cited "insurgent activity," including the threat of antiaircraft missiles, rocket-propelled grenades and rockets. Apart from worries about insurgent threats in Mali, the Algerian government has been keeping a close watch on airspace on its eastern border, where violence in Libya has led to flight bans there.

Spanish charter company Swiftair was operating the jet for the Algerian flag carrier. "We have no contact with the airplane," the Madrid-based company in a statement. The plane was due to land in Algiers at 6:10 a.m. local time, Swiftair said.

Swiftair operated two MD-83s planes for Air Algérie, one built in 1989 and the other in 1996, according to AeroTransport Data Bank, a French company that tracks airplanes. Privately-held Swiftair was established in 1986 and has a fleet of more than 30 planes. Most of the jets are older models such as Boeing 727s and 737s, as well as MD-83s.

All six crew aboard the missing Air Algérie airplane are Spanish nationals, according to Spain's main pilots' union.

France's foreign ministry said its embassies in Algeria and Burkina Faso were working with the airline and local authorities to locate the plane. France has a large military presence in the region with scores of troops operating in Mali, a landlocked country wedged between Algeria and Burkina Faso.

"We are totally mobilized," a French foreign ministry spokesman said.

France and Algeria have dispatched planes to Mali to search for the missing plane, a Malian government official said.

Mali's Communication Minister Mamadou Camara said the planes are searching a huge and sparsely populated swath of his West African country where the Air Algérie flight was last known to be flying.

"The zone is extremely vast," Mr. Camara said, adding that he had no further information about the circumstances under which the plane went missing. "To confirm that this plane crashed you must first find the site of the crash.," he said

Officials at Burkina Faso's National Civil Aviation Agency have set up a crisis room to field calls and assess reports on what might have happened to the missing plane. As phones rang loudly and officials shouted over each other in the background, one of the officials, Zoure Nana Guissou, said "We're in the process of assembling the info as quickly as we can."

The government's fast reaction illustrates how African air safety management has changed in recent years. A decade ago, when Africa accounted for about 25% of world-wide aviation fatalities but less than 4% of global traffic, governments often reacted slowly and chaotically to frequent accidents. While many African governments still lack resources to carefully monitor carriers, safety has improved significantly.

Outside assistance and pressure from the U.S., European Union and other regions has been a big factor, as has the arrival of more foreign carriers drawn by Africa's growing economies and resource boom. As a result, countries including Russia and Indonesia in some recent years have had worse safety records than much of Africa.

Nevertheless, accident rates in Africa remain typically higher than in the rest of the world as the continent struggles with poor infrastructure that has made flying there more difficult.

The International Air Transport Association said there were 61 accidents in the region between 2009 and 2013. The accident rate during the period was 13.47 crashes per million flight hours in Africa compared with the global average of 2.51 crashes.

IATA and the International Civil Aviation Organization have embarked on a program to lift African airline safety performance to global standards by next year.

Benoît Faucon in London, Inti Landauro in Paris, Dan Michaels in Frankfurt and Drew Hinshaw in Abuja contributed to this article.

Write to Christopher Bjork at christopher.bjork@wsj.com, Robert Wall at robert.wall@wsj.com and Stacy Meichtry at stacy.meichtry@wsj.com

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