WASHINGTON, Dec. 29 -- The Indonesian government has requested U.S. assistance in the search for the AirAsia jet that has gone into missing with 162 passengers on board since Sunday, U. S. Department of Defense confirmed Monday.

"The details of that request, which was made through the U.S. State Department, are still being coordinated but could include some air, surface and sub-surface detection capabilities," said DOD Press Secretary John Kirby in a statement.

"We stand ready to assist in any way possible," said Kirby.

The jet, which was en route from Surabaya, Indonesia, to Singapore, went missing not long after takeoff Sunday.

The rescue efforts expanded Monday, with more countries joining the sea and aerial search operations for the ill-fated Airbus A320- 200 plane.