A Chinese search plane discovered "suspicious objects" in the southern Indian Ocean on Monday, the official Xinhua news agency reported, raising the possibility that they could be from a Malaysia Airlines plane missing for over two weeks.
The crew of the IL-76 plane spotted two "relatively big" floating objects and several smaller white ones dispersed over several kilometers, Xinhua reported.
The Ilyushin or IL-76 is a large Russian-made, four-engine multipurpose aircraft,
China has also diverted its icebreaker ship, the Xuelong, or Snow Dragon, toward the location where the debris was spotted.
China has asked Australia to send its planes to the area to investigate, Xinhua said.
Later in the day, Australian authorities said a U.S. Navy P-8 Poseidon, the most advanced search aircraft in the world, had been unable to find objects spotted earlier by the Chinese Il-76 aircraft.
"A US Navy P-8 Poseidon aircraft was tasked to investigate reported object sightings by the Chinese aircraft made at 33,000 ft," an AMSA spokeswoman said in an emailed response to Reuters.
"The objects were spotted by the Chinese aircraft as it was heading back to Perth. Drift modelling was undertaken on the sighting. The P-8 was unable to relocate the reported objects."
The Chinese Ilyushin IL-76 aircraft spotted two "relatively big" floating objects and several smaller white ones dispersed over several kilometers, the Xinhua news agency reported earlier.
The reports came as Malaysian Prime Minister Najib Razak said on Monday that the Malaysia Airlines Flight MH370, which disappeared over two weeks ago en route to Beijing, crashed thousands of miles away in the southern Indian Ocean, citing new satellite data.
All 239 people on board were presumed dead, airline officials said.
Analysis of satellite information from British company Inmarsat had shown that the Boeing 777's last position was in the Indian Ocean west of Perth, Australia, Najib said in a statement.
"This is a remote location, far from any possible landing sites," he said. "It is therefore, with deep sadness and regret, that I must inform you that, according to this new data, Flight MH370 ended in the southern Indian Ocean."
He added that the families of the passengers and crew had been informed.
"For them, the past few weeks have been heart-breaking; I know this news must be harder still," he said.
(Additional reporting by Michael Martina in KUALA LUMPUR; Editing by Raju Gopalakrishnan and Nick Macfie)