Almost a week into its disappearance, authorities struggle to narrow down their leads as pressure mounts for answers to these burning questions: where is the MH370 flight and what had happened to it?

Malaysian authorities confirmed Friday evening that the search and rescue (SAR) operation continued to expand further: both east, into the South China Sea and further into the Indian Ocean.

“Normal investigation becomes narrower with time, but this is not a normal investigation,” said acting Transport Minister Datuk Seri Hishammuddin Hussein Friday evening, admitting that the information or the lack of thereof, is forcing the SAR to “look further and further”.

Currently, the multinational SAR involves 13 countries and more than 57 ships and 48 aircrafts scouring the land and sea.

‘Sabotage, hijack, still on the cards’

Today, at least two international reports suggested a possibility of a ‘deliberate’ action, pointing towards acts of sabotage or hijack.

An exclusive report by Reuters today said that military radar-tracking evidence had suggested that the MAS airline was “deliberately flown across the Malay peninsula towards the Andaman Islands”.

The report, citing sources familiar with the investigation, said an unidentified aircraft was following a route between navigational waypoints, indicating it was being flown by someone with aviation training.

"What we can say is we are looking at sabotage, with hijack still on the cards," according to a senior Malaysian police official the news agency quoted.

US officials on Friday have also pointed towards the possibility of a ‘manual intervention’, based on the belief that the shutdown of two communication systems on MH370 happened separately and “systematically”, according to an ABC News report.

The broadcaster quoted unnamed US investigators as saying that they believe the data reporting system was shut down at 1:07 am; while the transponder – which transmits location and altitude at 1:21 a.m.

“This indicates it may well have been a deliberate act,” said ABC News aviation consultant John Nance, while a source said that the US team "is convinced that there was manual intervention.”

Asked to comment on these reports, Hishammuddin continued to stress that all possibilities are not being ruled out. “The fact was that the transponder did not issue any signals. Whether it was deliberate or not, it is being investigated,” he reiterated.

Reports of satellite 'pings', search expands into Indian Ocean

Earlier in the morning also saw a major development where US confirmed that there were “indications” that the missing Boeing 777-200ER may have ‘went down’ in the Indian Ocean.

The USS Kidd, a destroyer, has been deployed to begin searches at an area where the Indian Ocean and the Andaman Sea meet.

US officials had reportedly claimed that MH370 continued to “ping” a satellite on an hourly basis after it lost contact with radar.

Hishammuddin however, did not specifically confirm or deny these reports, despite being repeatedly questioned by the media.

But, he said that the international investigating team are working together to share and go through data that included satellite information, adding that he won’t entertain reports quoting ‘unnamed officials’.

“Unless they come up with specifics, I don’t think I can entertain speculation from anybody,” he said.

Hishammuddin also listed several angles that both aviation and police investigations are still looking at, including whether the lost of contact with the transponder was “intentional, done under duress or because of an explosion”.

However, he stopped short of explaining, saying that he did not want to “go into the realm of speculations”.

Did MH370 really make ‘air turn back’?

He confirmed that one vital area that aviation investigators – including Federal Aviation Administration (FAA) and National Transportation Safety Board (NTSB) – are looking at was whether the aircraft made an ‘air turn back’.

“It goes back to the turn back issue, the experts are working to identify whether that was MH370 and we want to get verification. As soon as we find out, then we can focus into that area.”

“We are looking at the raw data, especially on the military side, whether we made the right decision (to search the West side).

“What if... what if… the plane is still on the South China Sea? It is totally irresponsible for us to do that (cancel the search),” he said.

Tremors on the seafloor

Meanwhile, Malaysian authorities have not received reports of a “seismic event” on the seafloor between Vietnam and Malaysia on March 8 that Chinese scientists claim was consistent with a plane crash, and could possibly be related to the missing MH370 aircraft.

Today, a Chinese university said signal came from two seismic monitor stations in Malaysia, which indicated that a slight tremor had occurred on the seafloor at about 2.55am on March 8, some 150 kilometres off the southern tip of Vietnam.

The tremor took place about 85 minutes after MH370 lost contact with air control, and about 116km northeast of the spot where it was reportedly last heard from.

On Vietnam’s downgrading of its search South China Sea, Hishammuddin said that he wanted to “look at it positively”.

Earlier today, Vietnam search spokesman Lt. Col. Nguyen Ngoc Son says the status of the hunt has switched from "emergency to regular."

“The cooperation with Vietnamese has been very positive to the extent that they allowed the SAR in their waters. Our position still stands,” said Hishammuddin. -- by Cynthia Ng and Teoh El Sen