Malaysia’s military says it is investigating reports that a missing Boeing 777 jetliner headed to Beijing changed course and made it to the Malacca Strait, hundreds of miles away from the last location reported by civilian authorities.

Malaysia Airlines said Tuesday that the western coast of the country, near the Malacca Strait, is "now the focus" of search efforts. That is on the other side of peninsular Malaysia from where Flight 370 was reported missing by civilian authorities, meaning if the plane went down there it would have had to fly over the country, presumably undetected. No debris from the plane has been found.

Civil aviation chief Azharuddin Abdul Rahman said expanding the search area didn't imply authorities believed the plane was off Malaysia’s western coast.

"The search is on both sides," he said.

But local newspaper Berita Harian quoted Malaysian air force chief Gen. Rodzali Daud as saying radar at a military base had detected the airliner at 2:40 a.m. on Saturday 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.

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

A Malaysian military official who has been briefed on the investigations, who spoke to Reuters Tuesday, also said the country’s military believes the plane was last tracked by radar over the Malacca Strait.

"It changed course after Kota Bharu and took a lower altitude. It made it into the Malacca Strait," said the official, who was not named. Kota Bharu is a city on Malaysia’s east coast.

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.

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.

The United States has sent two Navy ships, at least one of which is equipped with helicopters, and a Navy P-3C Orion plane with sensors that can detect small debris in the water. It said in a statement that the Malaysian government has done a "tremendous job" organizing the search efforts, which involve 40 planes and ships from at least 10 nations.

Vietnam's deputy military chief also said he had ordered a land search for the plane up to the border with Laos and Cambodia. He said that military units near the border with Laos and Cambodia had been instructed to search their regions also.

"So far we have found no signs (of the plane) ... so we must widen our search on land," said Lt. Gen. Vo Van Tuan, deputy chief of staff of Vietnamese People's Army.

The Chinese People's Liberation Army Daily newspaper said Beijing had deployed 10 satellites that will use high-resolution earth imaging capabilities and other technology to "support and assist in the search and rescue operations for the Malaysian Airlines aircraft."

Earlier Tuesday, Interpol said that the two passengers who used stolen passports to board the Malaysia Airlines flight were Iranians seeking asylum in Europe.

Interpol Secretary General Ronald K. Noble identified the men as Pouri Nourmohammadi, 19, and Delavar Seyedmohammaderza, 29. Noble said that the two men had traveled to Malaysia from Tehran using Iranian passports, but had secured stolen Italian and Austrian passports in Kuala Lumpur for their journey to Beijing and Amsterdam, for which both had tickets and planned to travel together.

Malaysian authorities said that Nourmohammadi planned to proceed from Amsterdam to Frankfurt, Germany, where his mother lives. The woman contacted authorities when her son failed to arrive as planned. The BBC reported that Seyedmohammaderza's intended final destination was Copenhagen, Denmark.

The disclosure by Interpol confirmed a report aired late Monday by the BBC's Persian service, which cited a friend of both men who hosted them at his home in Kuala Lumpur as they prepared to travel to Beijing, the final destination of the missing plane.

Over the weekend, the passports were identified as belonging to 30-year-old Austrian Christian Kozel and 37-year-old Italian Luigi Maraldi. Both men had reported that their passports had been stolen while they were traveling in Thailand.

It was not made immediately clear how the passports were sent from Thailand to Kuala Lumpur.

Sources told Fox News it is not uncommon for Iranians to travel to and from Malaysia, or to buy one-way tickets through third parties. They said the fact that the man believed to have purchased the tickets on behalf of two Iranians traveling with stolen passports seemed to be seeking the cheapest fares within a range of dates does not jibe with typical terrorism plots. The sources familiar with Iranian travel patterns also said use of stolen passports is common for those involved in the drug trade, those wanting to study or work abroad and even Iranians who seek political, religious or social refuge.

A BBC Persian editor told Britain's Daily Telegraph that the Iranians were "looking for a place to settle." Both Malaysia and Thailand are home to large Iranian communities.

"We know that once these individuals arrived in Kuala Lumpur on the 28th of February they boarded flight 370 using different identities, a stolen Austrian and a stolen Italian passport," Noble said, according to Reuters. But he added that Interpol believes no other suspect passports were used to board the plane.

“The more information we get, the more we are inclined to conclude it is not a terrorist incident,” he said.

Malaysia Airlines Flight 370 vanished from radar screens early Saturday local time with 239 people on board, shortly after takeoff from Kuala Lumpur. In the absence of any sign that the plane was in trouble before it vanished, speculation has ranged widely, including pilot error, plane malfunction, hijacking and terrorism. The last theory had focused on the reports that two stolen passports had been used by passengers on the plane.

China has urged Malaysia to speed up the search for the plane. About two-thirds of passengers and 12 crew members on the plane were Chinese, according to Reuters.

Frustrated relatives of some of the passengers on the flight claim that they have been able to call the cellphones of the missing travelers, but no one has picked up. Hugh Dunleavy, the commercial director at Malaysia Airlines, also said the airline heard ringing tones when it tried to call the crew members, the Straits Times reports.

But Malaysia Airlines spokesman Ignatius Ong dismissed the claims, saying he tried calling one of the phones five times and “got no answering tone,” according to News.com.au. He added that the airline’s command center had no luck either.

Relatives have not taken up “financial assistance” deals from Malaysia Airlines, who are offering around $5,000 to the families of each missing traveler.

“We’re not really interested in the money,” one relative told AFP, according to The Guardian. “It is all about the people -- the people on the plane. We just want them back.”

Malaysia Airlines also said it is investigating an Australia television report that the co-pilot on its missing flight had invited two women to stay in the cockpit for a flight two years ago.

Jonti Roos described the encounter on the program "A Current Affair." It aired multiple still photographs from Roos that showed the women inside the cockpit and the pilots apparently working the plane's controls.

The airline said late Tuesday it wouldn't comment about the report until its investigation is complete.

Roos said Fariq Abdul Hamid and the second pilot talked to her and her friend in the cockpit during the entire flight in December 2011 from Phuket, Thailand, to Kuala Lumpur.

Fox News' Lisa Daftari and The Associated Press contributed to this report.