Residents of Boeung Kak Lake light candles to spell "MH370" during a Buddhist ceremony, praying for the missing Malaysia Airlines MH370, in Phnom Penh March 17, 2014. The ceremony also included prayers for the release of 21 detainees who have be
Residents of Boeung Kak Lake light candles to spell "MH370" during a Buddhist ceremony, praying for the missing Malaysia Airlines MH370, in Phnom Penh March 17, 2014. REUTERS/Samrang Pring

At least three million people from around the world have joined a crowdsourcing project to help locate the week-old missing Malaysia Airlines flight MH370 airliner.

DigitalGlobe on Monday said its crowdsourcing project has enlisted some 24,000 square kilometres (9,000 square miles) of search area, with "map views" hitting 257 million and 2.9 million areas "tagged" by participants.

Lea Shanley, a researcher who studies crowdsourcing at the Woodrow Wilson International Centre for Scholars, told AFP that while she doubts it can locate the missing plane, the crowdsourcing project can help "identify where the aircraft is not located, thus saving critical time for the professional image analysts and responders."

On Monday, Australia took on the responsibility to lead the search-and-rescue efforts focused on the southern Indian Ocean.

Read: Malaysia Airlines MH370: 10 Days After, 3 Jet Takeover Theories, 600 Possible Landing Spots

Tony Abbott, Australian prime minister, said Malaysian Prime Minister Datuk Seri Najib Razak called him to ask for assistance.

"I told Prime Minister (Datuk Seri) Najib (Razak) that Australia stands with Malaysia at this very difficult time and would be pleased to take on this additional responsibility," Mr Abbott said.

The world's third-deepest and one of the most remote stretches of water in the world, the southern Indian Ocean has little radar coverage.

Read: Malaysia Airlines Retires MH370 Code, Now Part of History; US Experts Believe 'Manual Intervention' Deliberately Took Place in Missing Place

Meantime, U.S. Navy ships have dropped out of the search and rescue operations. The USS Kidd will return to its normal duties.

Instead, U.S. Navy search planes will now help locate the missing jetliner. A P3 Orion plane will move its base to Phuket, Thailand, and a P8 plane will be deployed to Perth, Australia.

"This is in no way a degradation of the mission," a Defense official told ABC News. "We're fully committed to the search operation and the fixed wing aircraft remains and is being shifted to a search area that's more conducive to aerial reconnaissance as opposed to surface searching."

Read: Malaysia Airlines MH370: Looking for a Needle in the Haystack, Uncoordinated Response Embarrasses Malaysians