The United States government is looking into the possibility of more of its citizens being on board the missing flight MH370.

US Embassy information officer Harvey Sernovitz said, that there are possibilities of passengers owning dual citizenships and different passports.

“We are also working with the airline to assess whether additional US citizens may have been on board,” Sernovitz told Astro AWANI.

The three US citizens listed on the Malaysia Airlines passenger manifest were Philip Wood, 51, and two children: Nicole Meng, four, and Yan Zhang, two.

Sernovitz also said that US assets deployed to help in the search and rescue (SAR) can increase the chances of a find.

"I think these have, from a technology perspective, these are radar and sonar that really help amplify the work being done by Msia as well as all of those, playing a very important role," he said.

Following a request by the Malaysian government, the US government had sent two navy ships, the USS Pinckney (DDG 91), an Arleigh Burke-class guided-missile destroyer which carries two MH-60R helicopters, and the USNS John Ericsson.

The US also sent a P-3C Orion aircraft that carries long-range search, radar and communications capabilities.

"The Orion has a lot of capabilities, radar and sonar, and has cameras. It is very useful in SAR environments, it can cover about 1500 sq miles an hour," said Sernovitz.

Sernovitz also said that the teams from National Transportation Safety Board (NTSB) and Federal Aviation Administration (FAA) are already in Malaysia to assist.