Malaysia's transport minister says a maintenance seal and other details prove that a wing part found on Reunion Island belongs to MH370, a claim other countries involved in the investigation have shied away from making.
Transport Minister Liow Tiong Lai said a maintenance seal on the flaperon matches the airline's records, though he didn't elaborate.
"From our first observation, the colour tone and all maintenance records that we have, we know. Our records show that it's the same as MH370," Liow said.
He said there are "many other technical details that I do not have to reveal" but that confirm the part is from Malaysia Airlines Flight 370.
Malaysian Prime Minister Najib Razak announced early on Thursday morning (local time) that the part, known as a flaperon, did indeed come from the doomed aircraft, but authorities in France, the US and Australia have stopped short of full confirmation.
The conflicting comments infuriated many families of those on board the plane, who have waited more than 500 days for concrete clues into the fates of their loved ones.
Dai Shuqin, the sister of one of the passengers, was among about a dozen Chinese relatives who held a demonstration outside Malaysia Airlines' offices in Beijing.
"France is being cautious about it, but Malaysia is desperate to put an end to this case and run away from all responsibilities," she said.
Liow said differences with other countries amounted to "a choice of words".
"They want to continue with additional tests. We respect their decision," Liow said of the French authorities.
Liow also said more apparent plane debris has been found on Reunion Island and sent to local authorities for French investigators to examine.
He said a Malaysian team found the objects, including a window and some aluminium foil, but the minister's press secretary later said it was "window material" rather than a window that was recovered.
"I can only ascertain that it's plane debris," Liow said.
"I cannot confirm that it's from MH370."
At a news conference in Paris, Deputy Prosecutor Serge Mackowiak declined to confirm that the flaperon belonged to MH370, though he said there were strong indications that it did.
"The very strong conjectures are to be confirmed by complementary analysis that will begin tomorrow morning," Mackowiak said.
"The experts are conducting their work as fast as they can in order to give complete and reliable information as quickly as possible."
The Australian government, which leads the seabed search for wreckage west of Australia, was also less certain than Malaysia, saying only that "based on high probability, it is MH370".
Publicly, Australian officials withheld criticism of Najib's announcement, with Australian Transport Minister Warren Truss saying Australia respected Malaysia's right to make that call, given it is the government in charge of the investigation.
Privately, however, there were questions about why Najib had moved forward with the statement before all countries had agreed.
An Australian government official, speaking on condition of anonymity, said Malaysia wasn't supposed to make the announcement, and had gone out on its own making a conclusive statement before getting the evidence to back it up.
Many families of those on board, who have waited nearly 17 months for tangible evidence, were fed up with the mixed messages.
"Why the hell do you have one confirm and one not?" said Sara Weeks, the sister of New Zealander Paul Weeks, who was on board.
"Why not wait and get everybody on the same page so the families don't need to go through this turmoil?"
Chinese relatives of the passengers said they had "serious doubts" over Kuala Lumpur's announcement that the wing part was from the aircraft.
In a handwritten statement posted on Chinese social media and signed "All MH370 passengers' relatives", they demanded a high-level Malaysian government representative meet them and "provide explanations".