Australian Prime Minister Tony Abbott during his visit to RAAF Base Pearce near Perth Monday. Pic: AP.

PERTH, Australia (AP) — Australia’s prime minister says the search for Malaysia Airlines Flight 370 is “an extraordinarily difficult exercise” but that it will go on as long as possible.

Tony Abbott said Monday that although no debris has been found in the southern Indian Ocean that can be linked to the plane missing for more than three weeks, the searchers are “well, well short” of any point where they would scale the hunt back.

Abbott says the best brains in the world are applying themselves to this task and adds: “If this mystery is solvable, we will solve it.”

The Boeing 777 disappeared March 8 while flying from Kuala Lumpur to Beijing with 239 people aboard.