HANOI, March 13 -- The cooperation between China and Vietnam in the search for a missing Malaysian plane is materialized by Hanoi's quick approval to Beijing's request for access to its water and airspace, a Vietnamese official said here on Thursday.

Vu The Chien, deputy chief of National Committee for Search and Rescue's Office, made the comment in an exclusive interview with Xinhua as multinational search and rescue operations continued into the sixth day.

However, the whereabouts of Malaysia Airlines' Flight MH370 operated on a Boeing 777-200 aircraft carrying 12 crew members and 227 passengers including 154 Chinese has not been known since it vanished from radar screens early Saturday morning on its way from Kuala Lumpur to Beijing.

"Although the two sides have not carried out joint operations, the cooperation is seen in Vietnam's approval for Chinese vessels and aircraft to implement their search mission in waters off Vietnam as quickly as possible," Chien said.

"Almost immediately" after receiving Chinese request, Vietnamese Ministry of Foreign Affairs, National Committee for Search and Rescue and Ministry of Defense work together to give greenlight to Chinese vessels and aircraft at least two days before they enter the search area, Chien added.

The procedures were simplified to facilitate Chinese search and rescue operations as the permission was made after phone consultation among Vietnamese officials, said Chien.

"We think that in rescue, there is the so-called golden hour," he said, meaning the importance of timely response to disaster.

"If we do our best as soon as possible, we will have high possibility of saving lives. If we are late for one or two minutes, things will be very different," the official noted.

"Chinese sides inform us of their direction of flying and location where they are. I think this shows a necessary collaboration," Chien praised.

Despite several exercises, cooperation between Vietnam and China in search and rescue, especially maritime, was not equivalent to the two countries' geographical proximity, he said.