The search for a missing Malaysia Airlines flight carrying 227 passengers and 12 crew members entered a third day on Monday as a multi-country search effort took hold.
About 40 ships and 22 aircraft from nine countries are taking part in the search effort, which was expected to resume at first light.
Fuad Sharuji, vice president of operations control at Malaysia Airlines, told CNBC on Monday that the airline had received several pieces of information that may be related to the missing aircraft but have so far proved negative.
"At the moment, we are as desperate as anyone else to find evidence at all," he said.
There are two oil slicks that are being analyzed by aviation authorities to confirm if they came from the flight. Officials are also looking at the possibility the jet disintegrated in mid-flight, Reuters reported citing a senior source.
"Certainly something unexpected happened and it had to be catastrophic in nature in order to prevent the crew from communicating it," said John Goglia, former member of the National Transportation Safety Board in the U.S. "That doesn't rule out mechanical failure and it doesn't rule out some sort of activity by person or persons unknown."
Some officials on Sunday had tied their hopes to debris. A Vietnamese navy plane spotted an object in the Gulf of Thailand that they suspect belongs to the Malaysian jetliner, the Civil Aviation Authority of Vietnam said on its website Sunday.
(Read more: Possible part of missing jet found, Vietnam says)
During the airline's press conference earlier this weekend, Malaysia's Department of Civil Aviation director-general Azharuddin Abdul Rahman said that there was still "no sign" of the aircraft and search efforts had intensified.
"The outcome so far [is] there is no sign of the aircraft… The research started at 7 a.m. this morning until 7 p.m. this evening. However, the ships will continue to do the search overnight," he said.
Rahman of Malaysia's Department of Civil Aviation added the search radius had been increased to 50 nautical miles from 20 nautical miles, and would include the Straits of Malacca following reports earlier in the day that the airline may have "turned back" from its scheduled route before disappearing over the South China Sea.
(Read more: Missing Malaysia Airlines jet may have turned back)
Tom Blinken, President Barack Obama's deputy national security adviser, said on NBC's "Meet the Press" Sunday that the U.S. government is "actively looking into all questions" raised by the disappearance of the missing flight. It was on route from Kuala Lumpur to Beijing
(Read more: What is the status of the missing jet investigation?)