Families aching for closure after their relatives disappeared aboard Malaysia Airlines Flight 370 last year vented their deep frustration Thursday at conflicting signals from Malaysia and France over whether the finding of a plane part had been confirmed.

"Why the hell do you have one confirm and one not?" asked Christchurch, New Zealand, resident Sara Weeks, whose brother Paul Weeks was aboard the flight that disappeared March 8, 2014 with 239 people aboard while en route from Kuala Lumpur to Beijing.

"Why not wait and get everybody on the same page so the families don't need to go through this turmoil?" she said.

Malaysia's prime minister announced overnight that a plane wing section found on the French island of Reunion in the Indian Ocean was "conclusively confirmed" to be from Flight 370, saying he hoped the news would end "unspeakable" uncertainty. The announcement was in line with the Malaysian conclusion that the plane crashed in the Indian Ocean, killing all aboard.

But French officials with custody of the wing part said only that there were strong indications the barnacle-encrusted part — known as a "flaperon" — was from the flight and that they would work further to try to confirm the finding Thursday.

"After 17 months, we need definite answers," Weeks said. "We need to progress, get answers, move toward further answers, and get some closure along the line."

About two-thirds of the passengers were from China, and in the Chinese capital, Xu Jinghong said she could not understand why Malaysian and French authorities did not make their announcement together.

"I am very angry — so angry that my hands and feet are cold," Xu, 41, said in an interview during the early hours of Thursday outside her home in downtown Beijing. "The announcement was made without experts from France present. I don't understand how the procedure can be like this."

The announcement overnight by Malaysian Prime Minister Najib Razak would appear to give the first strong physical evidence of a crash, which could put to rest several theories that many relatives have refused to rule out, including that the plane and its passengers were hijacked and intact in some still-secret location.

Irene Burrows, the 85-year-old mother of missing Australian passenger Rod Burrows, who was lost with his wife Mary, said in interview last year that she didn't expect the mystery of MH370's disappearance to be solved in her lifetime. She said at the time: "All I just want is a bit of the plane. It's all I want to know — where they are."

For her, Thursday's confirmation was a simple wish come true.

"We're quite pleased that it's been found," she said from her home in Biloela in Australia's northeast.

However, for many relatives, any potential certainty was diluted by the word from Paris, where Deputy Prosecutor Serge Mackowiak said the "very strong conjectures" that the wing part was from Flight 370 still needed to be "confirmed by complementary analysis" that would begin later Thursday.

It was unclear whether the mix-up was a result of miscommunication between the two countries, differing notions of the burden of proof or whether Malaysian officials were overeager to send out some definitive signal for relatives of the missing.

In any case, a full confirmation of the wing part wasn't likely to bring total closure for relatives, with the rest of the plane and the bodies still missing.

Jiang Hui, also 41, whose mother was on board, said that there was still a lack of evidence to prove that the plane crashed as was announced by Malaysian officials last year. At the time, they cited thorough analysis of the relatively limited satellite data available for the flight. Major questions still remain, including why the plane went off course, crossed back over Malaysia and went south into the Indian Ocean.

"The finding of debris does not mean the finding of our next of kin," Jiang said.

In Kuala Lumpur, Melanie Antonio — whose husband was a flight attendant on Flight 370 — said she wasn't sure how to feel.

"I'm numb, I'm not sad," she said. "It's just a flaperon, it doesn't prove anything. We still need the wreckage to prove. I just want anything that can tell me my hubby is gone."

Jacquita Gomes, also the wife of a flight attendant, echoed that sentiment. "If it's not too much to ask, I still want the remains of my husband."

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Associated Press writer Nick Perry in Wellington, New Zealand, video journalist Zhang Weiqun in Beijing, writer Rod McGuirk in Canberra, Australia, and photographer Joshua Paul in Kuala Lumpur, Malaysia, contributed to this report.