Beijing slammed Malaysia's "pretty chaotic" answers concerning the missing Malaysia Airlines plane, as Kuala Lumpur officials failed to pinpoint the plane's last known whereabouts.
In a statement late last night, foreign ministry spokesman Qin Gang said China had asked Malaysia to check conflicting information about the change of course of the jetliner, which vanished on Saturday with 239 passengers and crew aboard, including 154 Chinese.
As the search enters its sixth day, Malaysia's acting transport minister Hishammuddin bin Tun Hussein admitted: "We don't know where the aircraft is."
Guo Shaochun, head of the Chinese government task force in Kuala Lumpur, said Beijing "requests that Malaysia releases authoritative and substantial information" on the missing plane.
"It's pretty chaotic, so up to this point we too have had difficulty confirming whether [information is] accurate or not," said Qin, responding to conflicting information provided about the flight path of flight MH370.
"[China] has requested Malaysia to verify the 'turn-back' rumours and act accordingly," Qin later said in a statement on the ministry's website, "and notify the situation to China timely."
Military personnel from 12 countries and territories are sweeping seas and airspace around Southeast Asia for traces of the Boeing 777 jetliner.
The search has expanded to 27,000 square nautical kilometres, involving 42 ships and 39 aircraft, although Vietnam said it would scale back its efforts.
Malaysian officials in Kuala Lumpur were bombarded with questions about the contradictory statements on the plane.
Hishammuddin, quizzed about Beijing's frustration, said: "China obviously feels aggrieved because they have so many of their nationals involved." He added: "It's not a matter of chaos ... it only seems confused if you want it to be seen so."
Watch: Malaysia says hunt for jet not in disarray
Confusion reigned after reports indicated the plane had moved significantly off course.
Malaysia's air force chief, Rodzali Daud, denied reports quoting him saying the plane was last detected by military radar at 2.40am on Saturday at the northern end of the Strait of Malacca.
One Malaysian military official told the Post that while reviewing readings, he saw "weak signals" on the military radar showing an object moving west towards the Strait. Another Malaysian military investigator corroborated the sighting.
Watch: No idea where to look: the hunt for MH370 continues as mystery deepens
At a meeting in Beijing with passengers' families, Datuk Iskandar Sarudin, Malaysia's ambassador to China, said his country's national airline lost contact with the jet after communications were handed to air controllers in Ho Chih Minh City.
A spokesman for Vietnam's aviation authority confirmed the transfer took place. He said Vietnam could not communicate with the plane, told Malaysia, and passed responsibility back to Malaysia's aviation authority.
Danny Lee; Adrian Wan in Kuala Lumpur; Phila Siu in Phu Quoc Island, Vietnam; Stephen Chen, Sijia Jiang and Angela Meng in Beijing