The FBI is aiding the Malaysian government's search for an airliner missing for more than a week, the White House has confirmed, according to BBC News.
The U.S. investigators are believed to be helping the Malaysians search a home flight simulator belonging to one of the pilots of flight MH370 for clues.
The pilot is said to have deleted some files from the computer simulator.
Teams from 26 countries are trying to find flight MH370, which went missing on March 8 with 239 people on board.
Earlier, frustration with the search boiled over into chaotic scenes as Chinese relatives were dragged away from journalists in Malaysia's capital, Kuala Lumpur. They were attempting to speak to Chinese journalists outside the daily press conference.
BBC said its reporter was pushed away from the relatives, who were carrying banners criticizing the handling of the case. One of the relatives, a middle-aged woman, cried: "They give different messages every day! Where's the flight now? Find our relatives! Find the aircraft!"
The Malaysian government said later it regretted the scenes and ordered an investigation, saying "one can only imagine the anguish they are going through".