Vietnamese Air Force Col. Pham Minh Tuan uses binoculars on board a flying aircraft during a mission to search for the missing Malaysia Airlines flight MH370. Pic: AP.

KUALA LUMPUR, Malaysia (AP) — Vietnam says it has downgraded but not stopped its search for the missing jetliner in the South China Sea and has been asked by Malaysian authorities to consider sending planes and ships to the Strait of Malacca.

The statement Friday is a sign that the focus of the search effort is switching to the west of Malaysia, to the strait and further west into the Indian Ocean.

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It follows remarks by a U.S. official that the Boeing 777 sent signals to a satellite for four hours after the aircraft went missing early Saturday.

If that is true, then it vastly expands the area the lost jet might be.

Vietnam search spokesman Lt. Col. Nguyen Ngoc Son says the status of the hunt has switched from “emergency to regular.”