Searchers are racing against time to find the voice and data recorders. The devices emit "pings" so they can be more easily found, but the batteries last only about a month.
China's official Xinhua News Agency reported Saturday that the patrol vessel Haixun 01 detected a "pulse signal" Friday at 37.5 kilohertz — the same frequency used by the airliner's black boxes.
Houston confirmed the report and said the Haixun 01 detected a signal again on Saturday within 2 kilometers (1.4 miles) of the original signal, for 90 seconds. He said China also reported seeing floating white objects in the area.
The British navy ship HMS Echo, which is fitted with sophisticated sound-locating equipment, arrived in the area to join the search, Britain reported.
The Australian navy's Ocean Shield, which is carrying high-tech sound detectors from the U.S. Navy, will also head there, but will first investigate the sound it picked up in its current region, about 300 nautical miles (555 kilometers) away, Houston said.
Australian military aircraft are also being sent into the Haixun 01's area to investigate, he said.
In Kuala Lumpur, families of passengers aboard the missing plane attended a prayer service Sunday that also drew thousands of Malaysian supporters.
"This is not a prayer for the dead, because we have not found bodies. This is a prayer for blessings and that the plane will be found," said Liow Tiong Lai, president of the government coalition party that organized the two-hour session.
Two Chinese women were in tears and hugged by their caregivers after the rally. Several people wore T-shirts that read "Pray for MH370." Two-thirds of Flight 370's passengers were Chinese.
The crew of the Chinese ship reportedly picked up the signals using a hand-held sonar device called a hydrophone dangled over the side of a small boat — something experts said was technically possible but extremely unlikely. The equipment aboard the British and Australian ships is dragged slowly behind each vessel over long distances and is considered far more sophisticated.