China's official news agency says a ship searching for the missing Malaysian plane has detected a "pulse signal" in the southern Indian Ocean, according to the Associated Press.
The Australian government agency coordinating the search would not immediately comment on the report.
The multi-national search for the missing plane, which was last seen on March 8, has been centered on an area in the south Indian Ocean that is near Perth, Australia.
The Boeing 777 was en route from Kuala Lumpur to Beijing with 239 people aboard, including three Americans. No trace of the jet has been found so far.
Officials have said they are confident the flight crashed into the water after flying in a direction away from its intended destination for several hours.
This story was updated at 9:37 a.m.