China will not give up its search for the Malaysia Airlines jetliner that vanished early on Saturday as long as there is a glimmer of hope, Premier Li Keqiang vowed on Thursday.

"The families are very anxious. We are also anxiously waiting for information. People's lives are involved, and it is a top priority," he said when answering the first question at his NPC news conference.

Special: Malaysia Airlines plane missing

He also urged all parties to enhance coordination and handle appropriately issues related to the passengers' families.

The Beijing-bound Boeing 777-200, with 154 Chinese nationals among the 239 people aboard, vanished from radar screens after taking off from Kuala Lumpur.

Six days after the mysterious disappearance, 13 countries and regions, including China, Malaysia and Vietnam, have deployed nearly 40 aircraft and more than 40 ships in suspected crash areas in the South China Sea and Malacca Straits.

The multinational search team is combing 93,000 sq km of waters, an area the size of Hungary.

China has sent eight ships and five aircraft to the search mission and one more ship is on its way. It has also mobilized 10 satellites, and they have located three floating objects. But Malaysian acting Transport Minister Hishammuddin Hussein said nothing has been found at the site where the satellites spotted the objects.

Yan Dongmei, an official at the Institute of Remote Sensing and Digital Earth under the Chinese Academy of Sciences, said, "In previous efforts, the search area gradually narrowed as more information came in. But this time, the search zone keeps expanding."

The international effort to find the plane has been hampered by contradictory information, and no substantive clues have been found.

The Wall Street Journal reported on Thursday that the jetliner might have continued flying for four hours after its last contact with ground control, citing data from the plane's engines that are automatically transmitted to the ground as part of a routine maintenance program.

Malaysian authorities denied the report, saying it was inaccurate.

Hussein said the Malaysian government had contacted Boeing and Rolls-Royce, the engine manufacturer, and both said the last engine data was received at 1:07 am, several minutes before the plane lost contact over the South China Sea.

Richard Wray, director of external communications at Rolls-Royce, said: "We are currently not in a position to confirm or deny the report because flight data is supposed to be confidential until such time as the air accident investigator says otherwise. We are continuing to support Malaysia Airlines in its investigation."

As the search for the plane entered its sixth day, relatives of the Chinese passengers became increasingly impatient as they pressed for information.

Malaysia Airlines said on Thursday the MH370 flight code will be retired and replaced by MH318 from Friday. The service frequency will remain unchanged.

Contact the writers at pengyining@chinadaily.com.cn and hena@chinadaily.com.cn.