United States officials say the country is ready to help search for an AirAsia plane that disappeared while travelling from Indonesia to Singapore, but that so far it has not been asked.
The State Department said it was aware of the search and rescue operation underway being led by regional authorities, adding it "stands ready to assist in any way that's helpful".
The National Air Transportation Safety Board also said it was monitoring the situation and ready to aid the investigation if asked.
However, a Pentagon spokesman said it was not "aware of any requests for assistance" so far.
The State Department confirmed that none of the passengers was travelling on a US passport.
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The White House had said on Saturday that President Barack Obama had been briefed on the plane's disappearance and was monitoring the situation.
