Nothing related to missing Malaysia Airlines Flight MH370 were found so far in waters where suspicious objects had been spotted, said captain of the Chinese vessel Haixun 01 on Tuesday.

Jiang Long told a Xinhua reporter that the Chinese ships have already checked and ruled out a total of 11 locations in the southern Indian Ocean where suspicious objects had been seen in airborne observation or satellite images.

Also on Tuesday, new Australian coordination chief Angus Houston told reporters that the ongoing search for the missing plane could drag on for a long time.

The ex-Australian defense chief said the search and recovery operation "is the most challenging one that I have seen." Houston, who leads the newly established Joint Agency Coordination Center, said the crucial job now is to find the debris or wreckage of the missing plane, so as to narrow the search to a smaller area and use advanced equipments to locate the black box.

There are 11 planes and nine ships joining the search on Tuesday, according to Houston. More than three weeks after Flight MH370, with 239 people onboard, disappeared on March 8 en route from Kuala Lumpur to Beijing, its fate and whereabouts remain unknown.