U.S. Secretary of Defense Chuck Hagel speaks to members of a travel press pool on a plane en route to Honolulu, Hawaii April 1, 2014. REUTERS/Alex Wong/Pool

By Phil Stewart

HONOLULU (Reuters) - U.S. Defense Secretary Chuck Hagel said on Tuesday he expected to discuss lessons learned from the search for a missing Malaysian jetliner at talks with southeast Asian defense chiefs, but stopped short of criticizing Malaysia's coordination effort.

The so-far fruitless search for Malaysia Airlines Flight MH 370 has been a massive international military undertaking that has included patrol flights by state-of-the-art U.S. spy planes.

China has also put its own military build-up on full display, including dedicating high-resolution satellites and advanced warships to the hunt for the jetliner.

But Malaysian authorities face heavy criticism, particularly from China, for mismanaging the effort, now in its fourth week, and holding back information. Most of the 239 people on board the flight were Chinese.

Hagel did not direct blame at Malaysia, which has sent its defense chief to Hagel's three-day gathering of ministers from the 10-member Association of Southeast Asian Nations (ASEAN). But he portrayed the search for the jetliner as a learning opportunity.

"There's always lessons to be learned," Hagel told reporters traveling with him.

"We're going to go back, the Malaysians will go back, all the ASEAN nations will go back and walk through this. What could have been done? Maybe what should have been done?"

It was unclear from his remarks how much of that discussion might take place during the informal talks in Hawaii, which include sessions on disaster relief and humanitarian assistance.

A senior U.S. defense official, briefing reporters ahead of Hagel's trip, which will continue to Japan, China and Mongolia, said the Malaysia jet search effort highlighted "the importance of working together and cooperating."

"On the one hand it has shown that we have a number of countries that can come together and put aside rivalries and differences to work together," the official said, speaking on condition of anonymity. "On the other hand, it highlights that we have a lot further to go."

The official stressed the need for deeper cooperation on an ongoing basis, so that nations could be better positioned to cooperate upon crises like the jetliner's disappearance.

Malaysia says the plane was likely diverted deliberately, probably by a skilled aviator, leading to speculation of involvement by one or more of the pilots. Investigators, however, have determined no apparent motive or other red flags among the 227 passengers and 12 crew.

Malaysia's defense minister, who is also acting transport minister, Hishammuddin Hussein, has said he would discuss the deployment of "more specific military assets" for the search during the talks in Hawaii.

Hagel noted that he has met all of Malaysia's requests since the jetliner dropped from civilian radar in the early hours of March 8 as it flew from Kuala Lumpur to Beijing.

"I've talked to the minister twice personally about this. We have complied with those requests," Hagel said.

The search is now focused on a vast, inhospitable swathe of the southern Indian Ocean west of the Australian city of Perth, but an international team of planes and ships have so far failed to spot any sign of the jetliner.

(Editing by Lisa Shumaker)