“Each country will have to ask itself: What are the prospects of further investigation and the cost-benefit of it?” said Ramon Navaratnam, chairman of the Center for Public Policy Studies at the Asian Strategy and Leadership Institute in Kuala Lumpur. “If there’s no prospect, there’s no prospect: We have to be very realistic. But it’s a very difficult decision to make. It’s like someone on a medical support system and you have to determine whether to pull the wires or not.”

Until now, the costliest search and recovery effort ever undertaken followed the crash of Air France Flight 447 hundreds of miles off the coast of Brazil in 2009, reaching about 115 million euros, roughly $160 million at the time, over the course of two years, according to estimates by experts who participated in that effort.

But the search for Flight 370 is already far more complicated, and may have already topped that total. Some of the ships involved cost hundreds of thousands of dollars a day apiece to use, and some of the aircraft being used can cost thousands of dollars an hour each to operate, officials say.

While there is an international convention that determines responsibility for air accident investigations, there are no protocols or treaties that dictate who pays, experts said. The most likely case is that the countries and companies participating in the search for Flight 370 will bear their own costs, several analysts predicted.