Day two of search operations for the missing MH370 on Sunday has been intensified with the involvement of more parties, a wider search area and several new leads uncovered.

The operation was led by the Malaysian armed forces accompanied by American, Vietnamese, Singaporean, Indonesian and Philippine troops, involving both the air and navy bases.

New leads have also emerged indicating that the missing aircraft made an 'air turn back' (the return of an aircraft to air port origin as a result of suspected malfunction).

Royal Malaysian Air Force chief Tan Sri Rozali Dau said the army’s radar records showed signs that the aircraft tried to make an air turn back and that it was supported by the civil radar.

“We have seen the radar record, there is a possibility of the flight making an air turn back. We are still checking with other international agencies, there is the possibility that the aircraft returned to KLIA,” he said at a press conference, referring to the Kuala Lumpur International Airport.

This new information added to the mystery surrounding the aircraft as the MH370 did not send out any emergency signals and did not report the attempt for an air turn back, if it had actually done so.

Meanwhile, the investigation into the missing aircraft had also focused if there were elements of terrorism with the confirmation that two of the passengers on board had used false passports.

"The two passengers, captured by the KLIA’s closed circuit cameras, are currently being investigated," said Department of Civil Aviation director-general Datuk Azharuddin Abdul Rahman.

“We have CCTV recordings from the check-in up to departure,” he said.

An Italian, Luigi Maraldi, whose name was in the MH370 passenger manifest, did not board the plane.

According to the Italian Foreign Ministry, Maraldi’s passport was stolen last August in Thailand.

An Austria passenger, Christian Kozel, whose name was also on the passenger list, had reported his passport missing while on holiday in Thailand two years ago.

Acting Transport Minister, Datuk Seri Hishammuddin Hussein said earlier reports stated that four people on the ill-fated plane had used false passports but investigations later revealed there were only two - the Italian and Austrian.

The passengers involved had reportedly bought their tickets from China Southern Airlines, a code share flight with Malaysia Airlines for the Kuala Lumpur- Beijing route.

The Chinese carrier also announced that it had sold tickets to seven MH370 passengers including a Chinese national, a Dutch national, one Malaysian and two Ukrainians.

Meanwhile, Azharuddin said the luggage belonging to five passengers were removed from the aircraft before take-off as they did not board the plane.

The Malaysia Maritime Enforcement Agency (APMM) had also confirmed spotting oil spills at about 20 nautical miles south from where the MH370 flight was last detected before it vanished off the radar.

APMM director-general Datuk Mohd Amdan Kurish said his team had spotted the oil spill at about 11am, Sunday morning.

“A ship has been sent to the area to obtain samples of the oil spill and to confirm if it indeed came from a plane,” he said.

In a related incident, China’s civil aviation director said debris had also been detected, believed to be from the MH370 flight, but it is still being investigated.

Meanwhile, Malaysia Airline said it understood the people’s concern on wanting to know the latest updates regarding the missing MH370 flight but added the families of passengers were now its main priority.