Malaysia's air force chief has denied an earlier media report that the military last tracked a missing Malaysia Airlines jetliner over the Strait of Malacca, far west from where it last made contact with civilian air traffic control when it disappeared four days ago.

"I wish to state that I did not make any such statements," Malaysian air force chief Rodzali Daud said in a statement on Wednesday.

Local newspaper Berita Harian had quoted Daud as saying radar at a military base had detected the airliner at 2:40 a.m. local time near Pulau Perak at the northern approach to the strait, a busy waterway that separates the western coast of Malaysia and Indonesia's Sumatra island.

"After that, the signal from the plane was lost," he was quoted as saying.

Reuters has now reported that Daud denied making such a statement.

A senior military official said earlier Tuesday that the Malaysian military had radar data showing the missing Boeing 777 jetliner changed course and made it to the Malacca Strait, hundreds of kilometres from the last position recorded by civilian authorities.

A high-ranking military official involved in the investigation confirmed the report and also said the plane was believed to be flying low. The official spoke on condition of anonymity because of the sensitivity of the information.

Authorities had earlier said the plane, which took off at 12:20 a.m. and was headed to Beijing, may have attempted to turn back to Kuala Lumpur, but they expressed surprise that it would do so without informing ground control.

The search for the plane was initially focused on waters between the eastern coast of Malaysia and Vietnam, the position where aviation authorities last tracked it. No trace of the plane, which was carrying 239 people, has been found by the 40 planes and ships from at least 10 nations searching the area.

Sources: CBC News stories, Reuters, AP (CBC)

Earlier Tuesday, Malaysia Airlines said in a statement that search and rescue teams had expanded their scope to the Malacca Strait. An earlier statement said the western coast of Malaysia was "now the focus," but the airline subsequently said that phrase was an oversight. It didn't elaborate. Civil aviation chief Azharuddin Abdul Rahman said the search remained "on both sides" of the country.

Also Tuesday, authorities said two people who boarded the flight using stolen passports were Iranians who had purchased tickets to Europe. Their appearance on the flight had raised speculation of a possible terrorist link.

Malaysian police chief Khalid Abu Bakar said investigators had determined one was a 19-year-old Iranian, Pouria Nourmohammadi Mehrdad, and that it seemed likely he was planning to migrate to Germany.

"We believe he is not likely to be a member of any terrorist group," Khalid said.

Switched passports

Interpol identified the second man as Seyed Mohammed Reza Delavar, a 29-year-old Iranian, and released an image of the two boarding a plane at the same time. Interpol Secretary General Ronald K. Noble said the two men travelled to Malaysia on their Iranian passports, then apparently switched to their stolen Austrian and Italian documents.

Stunt man aboard A stunt man whose credits include the acclaimed martial arts epic The Grandmaster and other films was among the passengers on a missing Malaysia Airlines flight. Ju Kun also worked on The Forbidden Kingdom. He was scheduled to work on a joint Weinstein Co. and Netflix production, the pilot of a new series Marco Polo, at a studio in Malaysia before he boarded the Malaysia Airline flight to return home to Beijing.

He said speculation of terrorism appeared to be dying down "as the belief becomes more certain that these two individuals were probably not terrorists." He appealed to the public for more information about the two.

Malaysia Airlines, meanwhile, said it is investigating an Australian television report that the co-pilot on the missing plane had invited two women into the cockpit during a flight two years ago.

Jonti Roos described the encounter on Australia's A Current Affair. The airline said it wouldn't comment until its investigation is complete.

Roos said she and her friend were allowed to stay in the cockpit during the entire one-hour flight on Dec. 14, 2011, from Phuket, Thailand, to Kuala Lumpur. She said the arrangement did not seem unusual to the plane's crew.

"Throughout the entire flight, they were talking to us and they were actually smoking throughout the flight," Roos said.

Roos didn't immediately reply to a message sent to her via Facebook.

The missing plane took off from Kuala Lumpur, on the western coast of Malaysia, early Saturday en route to Beijing.

It flew across Malaysia into the Gulf of Thailand at 11,000 metres and then disappeared from radar screens.

Vast search area

The hunt began on Saturday near the plane's last known location. But with no debris found there, the search has been systematically expanded to include areas the plane could have reached with the fuel it had on board. That is a vast area in which to locate something as small as a piece of an aircraft.

China, where two-thirds of the passengers are from, urged Malaysian authorities on Tuesday to "speed up the efforts" to find the plane. It has sent four ships, with another four on the way.

One of the two men travelling on a missing Malaysian Airlines jetliner was an Iranian asylum seeker, officials said Tuesday, as baffled authorities expanded their search for the Boeing 777. (Wong Maye-E/Associated Press)

A shopping mall in Beijing suspended advertising on its large outdoor LED screen to display a search timer — an image of an airplane along with a digital clock marking the time since contact with the flight was lost.

Assuming the plane crashed into the ocean or disintegrated in midair, there will likely still be debris floating in the ocean, but it may be widely spread out and much may have already sunk. In past disasters, it has taken days or longer to find wreckage.