Australia was tasked with taking responsibility for part of the search for Malaysia Airlines flight MH370 Monday, as the operation to locate the aircraft widened to 25 countries and investigators reportedly said they believe the plane may have flown dangerously low to avoid detection.

Australian Prime Minister Tony Abbott said Australia would manage the search along the “southern vector” of the possible flight path of missing jet, which disappeared over a week ago.

The Malaysian government has revealed an investigation indicates the jet was deliberately diverted and flew for several hours after leaving its scheduled flight path — either north towards Central Asia, or towards the southern Indian Ocean.

Investigators now say that the plane may have flown at an altitude of 5,000 feet to avoid radar detection, using a dangerous method called terrain masking, The Sydney Morning Herald reported Monday.

The maneuver is used by stealth pilots in military operations, but flying so low with a much bulkier Boeing 777 could put the plane and passengers in danger, the paper reported.

Abbott, who earlier Monday told journalists he had no information that the flight may have come close to Australia, said he was responding to a request from Malaysian Prime Minister Najib Razak.

“He asked that Australia take responsibility for the search on the southern vector, which the Malaysian authorities now think was one possible flight path for this ill-fated aircraft,” Abbott told parliament.

“I agreed that we would do so. I offered the Malaysian prime minister additional maritime surveillance resources which he gratefully accepted.”

Abbott said the defense chiefs of Australia and Malaysia were discussing how to implement the arrangement.

“Australia will do its duty in this matter. It will do our duty to ensure that our search and rescue responsibilities are maintained and upheld,” he said.

“And we will do our duty to the families of the 230 people on that aircraft who are still absolutely devastated by their absence and who are still profoundly, profoundly saddened by this as yet unfathomed mystery.”

Asked earlier whether Australian agencies had detected the plane close to Australia, given its western coast borders the Indian Ocean, Abbott said: “I don’t have any information to that effect.

“But all of our agencies that could possibly help in this area are scouring their data to see if there’s anything that they can add to the understanding of this mystery,” he told reporters.

Given that a northern route would have sent the plane over countries with busy airspace, most experts say the person in control of the aircraft would more likely have chosen to go south. The southern Indian Ocean is the world’s third-deepest and one of the most remote stretches of water in the world, with little radar coverage.

Australia has a powerful military radar system with an approximate range of 1,900 miles used to monitor the Indian Ocean west of the country. But the radar would have to have been pointed in the right direction at the right time to have picked up detailed flight activity, said John Blaxland of the Australian National University’s Strategic and Defence Studies Centre.

Without any alarms triggered at the time, the radar data probably would have recorded at most a blip on a screen, which likely wouldn’t provide enough information to track the plane, Blaxland said Monday.

“So to expect that’s going to deliver some kind of miraculous tracking of an aircraft over a week ago … I think we might be a bit disappointed,” Blaxland said.

Australia has two Orion surveillance aircraft assisting with the search for the plane, which was en route to Beijing when it disappeared. Abbott said one of those had now been redeployed to the Indian Ocean.

While countries join the search for the plane, investigators in Kuala Lumpur have delved into the backgrounds of the crew and passengers, looking for possible terror ties.

Malaysia’s police chief, Khalid Abu Bakar, said he asked countries with citizens on board the plane to investigate their backgrounds, no doubt looking for anyone with terrorism ties, aviation skills or prior contact with the pilots. He said that the intelligence agencies of some countries had already done so and found nothing suspicious, but he was waiting for others to respond.

Police searched the homes of both pilots Saturday, the first time they had done so since the plane vanished, the government said. Asked why it took them so long, Khalid said authorities “didn’t see the necessity in the early stages.”

Police confiscated the elaborate flight simulator that one of the pilots, Zaharie Ahmad Shah, had built in his home and reassembled it in their offices to study it for clues, Khalid said.

Zaharie, 53, who has three grown children and one grandchild, had previously posted photos online of the simulator, which was made with three large computer monitors and other accessories. Earlier this week, the head of Malaysia Airlines said the simulator was not in itself cause for any suspicion.

Malaysian police were also investigating engineers and ground staff who may have had contact with the plane before it took off, Khalid said.

Authorities have said someone on board the plane first disabled one of its communications systems — the Aircraft and Communications Addressing and Reporting System, or ACARS — about 40 minutes after takeoff. The ACARS equipment sends information about the jet’s engines and other data to the airline.

About 14 minutes later, the transponder that identifies the plane to commercial radar systems was also shut down. The fact that both systems went dark separately offered strong evidence that the plane’s disappearance was deliberate.

On Sunday, Malaysian Defense Minister Hishammuddin Hussein told a news conference that the final, reassuring words from the cockpit — “All right, good night” — were spoken to air traffic controllers after the ACARS system was shut off. Whoever spoke did not mention any trouble on board.

Whoever disabled the plane’s communication systems and then flew the jet must have had a high degree of technical knowledge and flying experience, putting one or both of the pilots high on the list of possible suspects, Malaysian officials and aviation experts said.

Zaharie, the captain, was a supporter of a Malaysian opposition political party that is locked in a bitter dispute with the government, according to postings on his Facebook page and a friend, Peter Chong, who is a party member.

Six Australians were on board the commercial flight carrying 239 passengers and crew which vanished on March 8 in a busy Southeast Asian sky, and relatives have clung to hope that their loved ones may still be alive.

“I haven’t got a clue what is going on, but maybe they have been hijacked and that gives me hope,” David Lawton, whose brother Bob was aboard MH370, told the Australian Broadcasting Corporation on Monday.

“In this day and age and the technology we have you would think they would be able to find it, but no, apparently they can’t.

“I don’t blame anybody for it, I just want to know what their fate was,” he added.

Abbott said the incident could lead to changes in how aircraft are tracked.

“I think that there will be a lot of analysis done of this particular event which thus far remains deeply, deeply mysterious,” he said.

“And I think there will be a lot of lessons learnt, and I dare say some of those lessons will involve the tracking of aircraft.”