A relative of a passenger aboard missing Malaysia Airlines flight MH370 uses her phone at a remembrance event for missing Malaysia Airlines flight MH370 on the one year anniversary of its disappearance, in Kuala Lumpur, March 8, 2015. Reuters/Olivia Harris

Malaysia Airlines Flight MH370, which went missing on March 8, 2014, with 239 people on board, “will be found in the next year,” Martin Dolan, chief commissioner of the Australian Transport Safety Bureau (ATSB) said Thursday. An unprecedented international search for the plane has crossed 500 days but has so far yielded no concrete clues as to the whereabouts of the jet.

Two vessels, Fugro Discovery and Fugro Equator, are currently conducting search operations in the southern Indian Ocean, Joint Agency Coordination Centre, which is supervising the search out of Australia, said in its latest update this week. Over 21,000 square miles of the 46,332 square miles of search area has been scoured.

"Once we started looking and defining the search area, it became quite clear it could take up to two years,” Dolan said, according to U.K.’s Daily Express. "We still remain confident it will be found in the next year.

"All the analysis we have puts the aircraft somewhere in that large search area. We have no more information that would allow us to calculate a different area and governments accept that," Dolan reportedly added.

Since the plane’s disappearance, several theories have emerged with some experts questioning the location of the current search. However, Dolan reportedly rejected the theories.

“All the information we have puts the aircraft in this defined search area. The crews and equipment being used are excellent and the data we're receiving is of a quality beyond the specifications yet,” Dolan reportedly said. "If we have to search the entire area, it will be completed this time next year but we expect to find the aircraft before then."

Last month, industry experts criticized Australia’s decision of choosing Fugro NV for the search operation, claiming that the company’s search methods were ineffective, and that it was using the wrong technology and inexperienced personnel. However, ATSB refuted the assertions and defended its handling of the search for Flight MH370.

“These attacks are unfounded and unfair,” Dolan said in a statement, at the time. “The search for MH370 represents thousands of hours of work by hundreds of people who are dedicated, expert and professional. They are fully committed to finding the aircraft.”

The search operation, which is being headed by Australia, has become the costliest in aviation history.