HANOI, March 12 -- The missing Malaysian jetliner seemed unlikely to have fallen in water off Vietnam as the country has conducted intensive search and no clues have been found so far, some senior Vietnamese officials said here Wednesday.

Tran Quang Khue, deputy chief of staff of Vietnam People's Army told a daily briefing that strong forces have been put into the search in waters between Vietnam and Malaysia to the right of the air route of the missing plane over the past few days when favorable weather there made observation easier. Yet no trace of the flight MH370 had been detected so far.

Vietnam will maintain the number of vessels for search mission while readjusting frequency of their voyage to suit the changing situation, the official added.

Do Ba Ty, chief of staff of Vietnam People's Army said at the briefing that Vietnam has showed great concern and perseverance in search for the lost plane in the past few days.

He said search efforts will continue in areas that have not been reached, but with fewer vessels involved from Thursday and some vessels on a standby status. These vessels should be ready to join the search at short notice when necessary.

Vo Van Tuan, deputy chief of staff of Vietnam People's Army said Vietnam would continue to expand its search on Thursday with nine vessels and eight aircraft.

Two among these aircraft will be flying for search while the others stay ready on the coast, said Tuan, adding that constant flights will be maintained in consecutive order.

He said Vietnam will not rule out any possibilities or give up search efforts, though no clues had been found so far. As an experienced pilot, Tuan noted that it often took days to find out clues from a missing plane.