The new search area is closer to Perth than the previous one, with a flying time of 2 1/2 hours each way, allowing for five hours of search.
AMSA said 10 planes will join the search Sunday. The first aircraft to leave the Perth air force base, a Chinese Ilyushin IL-76, was already over the area.
The Australian navy supply ship HMAS Success, which is to store any wreckage found, and three Chinese ships reached the search area Saturday. Six more ships will arrive Sunday, AMSA said.
The ships are trying to locate and identify the objects sighted by aircraft over the past two days.
There were light showers and low cloud in the area, but not enough to disrupt the search, AMSA said.
Dunleavy, the Malaysia Airlines' director, said in Beijing the Chinese relatives flew to Kuala Lumpur on Sunday morning.
Steve Wang, a representative of some of the Chinese families in Beijing, said the relatives are demanding more answers because they were not satisfied by the responses Malaysian government representatives gave them in China.
"We have demanded that we meet with the prime minister and the transportation minister," said Wang Chunjiang, whose younger brother, Wang Chunyong, was on Flight 370. "We have questions that we would like to ask them in person."
If investigators can determine that the plane went down in the newly targeted search zone, recovery of its flight data and cockpit voice recorders could be complicated.
Much of the sea floor in the area is about 2,000 meters (6,600 feet) below the surface, but depths may reach up to 6,000 meters (19,685 feet).
Wong reported from Kuala Lumpur. Associated Press writers Scott McDonald and Eileen Ng in Kuala Lumpur; Kristen Gelineau in Sydney; Rod McGuirk in Canberra, Australia; Nick Perry in Wellington, New Zealand; and Aritz Parra and Didi Tang in Beijing contributed to this report.
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