HANOI, March 13 -- Vietnam is asked by the Malaysian side to assist search in waters off the Malaysian coast, a Vietnamese official said on Thursday over the upcoming search plan for the missing Malaysian jet.

Vu The Chien, deputy chief of Vietnam's National Committee for Search and Rescue, told Xinhua reporters here that Malaysia made the proposal through phone.

Vietnam is considering the option, said Chien, adding that the country will conduct its search efforts till the missing plane is located.

On Thursday morning, Vietnam deployed four planes for the search mission, he said. These planes flew along the expected air route of the Malaysian jetliner, expanding to the Gulf of Thailand and further to the east. A low-flying aircraft took off from Ca Mau cape and flew along the Vung Tau coast as the area is covered with mangrove and less populous, said Chien.

Vietnam further extended its search on Thursday afternoon, he added.

Vietnam has sent seven vessels to the waters between Vietnam and Malaysia on Thursday, according to Chien.

After exchanging talks with military attaches of the Malaysian embassy and the Singaporean embassy to Vietnam early Thursday morning about the signal detected in the Malacca Strait, the three sides concluded that they should continue the search mission.

Two additional Vietnamese aircraft have flown to the area where three floating objects were spotted by Chinese satellites, but nothing has been found so far.

A Vietnamese vessel is on the way to the area for further check, said Chien, adding that Vietnam will not leave out any possible clues for finding the missing plane.