Malaysia Airlines Flight MH370 Leaders Say Search Won't Stop

Leaders of the two countries heading multinational efforts to solve the mystery of Malaysia Airlines Flight 370 pledged Thursday that no effort would be spared to give the families of those on board the answers they need.

[caption id="attachment_2038" align="alignnone" width="620"] Australian Prime Minister Tony Abbott, right, chats with his Malaysian counterpart Najib Razak at Perth International Airport as Razak prepares to depart Australia after his visit during the search of the missing Malaysia Airlines flight MH370, in Perth on Thursday. Najib met with Abbott and got a briefing by Angus Houston, the head of a joint agency co-ordinating the search. (Paul Kane/Associated Press)[/caption]

Malaysian Prime Minister Najib Razak flew to Australia for briefings on the search for the missing plane and talks with his Australian counterpart, Tony Abbott, whose country is overseeing the hunt in a huge and remote patch of the Indian Ocean.

"It is a very difficult search — the most difficult in human history. But as far as Australia is concerned, we are throwing everything we have at it," Abbott said in a media appearance with Najib.

No trace of the Boeing 777 has been found nearly four weeks after it vanished in the early hours of March 8 on a flight from Kuala Lumpur to Beijing with 239 people on board.

Ten planes and nine ships were involved in search operations Thursday, scouring the ocean far off Australia's southwest corner where investigators believe the plane may have ended up after unknown events occurred on board.

Najib, whose government has been harshly criticized by some victims' families for giving sometimes conflicting information about the flight and for the slow pace of the investigation, said everyone involved in the search is thinking of the families of victims who are waiting desperately for news.

"I know that until we find the plane, many families cannot start to grieve," Najib said. "I cannot imagine what they are going through. But I can promise them that we will not give up.