On Tuesday, Inspector General Khalid Abu Bakar identified a man who boarded the flight with a stolen Austrian passport Saturday as a 19-year-old Iranian trying to migrate to Germany via Beijing and Amsterdam. Bakar said authorities continue to investigate the identity of the man who boarded at Kuala Lumpur International Airport using a stolen Italian passport.

Security at the airport has come under scrutiny. However, Bakar said that rumors of passengers who had checked in but not boarded were unfounded.

"Everybody who booked this flight boarded the plane," Bakar said Tuesday.

Bakar said authorities had examined hijacking, sabotage, suicide, malfunction and even potential life insurance fraud. However, Bakar said the Iranian, identified as Pouria Nour Mohammad Mehrdad (left in photo), seemed likely to have tried to migrate to Germany using an Austrian passport, according to interviews with the teenager's mother, who had expected him to arrive in Frankfurt.

So far, theories as to what might have happened to the plane have often served to deepen the mystery.

In a separate press conference on Tuesday, Interpol officials said they continued to look into terrorism, organized crime, and potential human trafficking or smuggling while investigating the disappearance. Interpol Secretary-General Richard Noble said, though, that for the sake of the passengers' families putting an end to the uncertainty surrounding the flight, "not terrorism, not stolen passports, not conspiracy theories, was our very first thought."

'Support and assist'

Authorities expanded their search on land and sea Tuesday, reflecting the difficulties in finding traces of the Boeing 777 three days after it vanished with 239 people on board. In the absence of evidence, speculation over the possible causes has ranged wildly.

Chinese satellites will "support and assist in the search and rescue operations for the Malaysia Airlines aircraft," the People's Liberation Army Daily reported on Tuesday in an article carried on the Defense Ministry's website. The satellites were reprogrammed by the Xi'an Satellite Control Center in northwest China to aid in the search effort. They will also help with weather monitoring and assist communication during the search in the area where the plane disappeared, the newspaper reported.

China, home to two-thirds of the passengers, urged Malaysia to "speed up the efforts" and has contributed ships and helicopters to the search. China has also supplied Malaysian officials with photographs of its 153 nationals aboard Malaysia Airlines Flight MH370.

Mystery over sea

The plane vanished off radar screens early Saturday morning en route to Beijing from Kuala Lumpur at 35,000 feet (11,000 meters), roughly in between the east coast of Malaysia and southern Vietnam. According to the airline, the pilots didn't send out any distress signals, which suggests a sudden and possibly catastrophic incident.

Dozens of planes and ships from several nations have searched for the jetliner. If the plane crashed into the ocean or disintegrated in midair, debris would likely continue to float in the sea, but the bulk of it may already have sunk.

A New Zealand Air Force plane will join the search, Prime Minister John Key said Tuesday. Key said the Royal New Zealand Air Force P3 Orion aircraft had left New Zealand and should arrive Tuesday afternoon.

The United States has sent two navy ships, at least one equipped with helicopters, and a Navy P-3C Orion plane with onboard sensors that allow the crew to clearly detect small debris in the water. The US announced in a statement that the Malaysian government had done a "tremendous job" organizing the land and sea effort, which began on Saturday morning at the plane's last known point.

With no debris found, the search has systematically expanded to include areas where the plane could have in theory ended up given the amount of fuel it had on board - an area many thousands of square kilometers wide.

"We are as anxious as the families to know the status of their loved ones," Malaysia Airlines announced in a statement Tuesday.

mkg/hc (Reuters, AFP, dpa, AP)