KUALA LUMPUR, Malaysia — A Chinese vessel that is part of a multinational search for the missing Malaysia Airlines plane in the southern Indian Ocean reported Saturday that an underwater sensor had picked up a "pulse signal" of the same frequency used by locator devices on planes, China's official news agency reported.
The devices, which use a frequency of 37.5 kilohertz, are attached to aircraft data and voice recorders, commonly known as black boxes, which are crucial to determining the causes of airplane crashes.
Hours after the report, the Australian chief coordinator of the ocean search, Angus Houston, said in a statement, "The characteristics reported are consistent with the aircraft black box." He also noted that white objects had been spotted floating in the water about 55 miles from the area where the sounds were heard.
But he urged caution, saying the reports could not be immediately verified — a sentiment also expressed by Malaysian and Chinese officials.
"There is no confirmation at this stage that the signals and the objects are related to the missing aircraft," said Houston, chief of the Joint Agency Coordination Center, an Australian government group. False alerts can be triggered by sea life, including whales, or by noise from ships. Australian officials reported last week that an alert sounded on a British Royal Navy vessel, the HMS Echo, which is equipped with black box detection equipment, but the signal turned out to be false.
A reporter from China's main state-run TV network, CCTV, who was on the Chinese ship, the Haixun 01, reported that the vessel's crew had heard a signal Friday as well. A reporter from Xinhua, China's official news agency, was also aboard the vessel.
Today, Australia's coordination center said 12 planes and 13 ships would search three zones 1,200 miles northwest of Perth. The pulse signal reported by the Haixun 01 appeared to be south of two of those areas and east of the third. According to coordinates provided by Xinhua, the vessel was searching about 1,020 miles northwest of Perth on Saturday.
Despite the lack of confirmation, the news from the Chinese ship generated excitement about the possibility that after four weeks of fruitless searching, officials might finally be zeroing in on concrete evidence of the plane and its fate.
Since Flight 370 veered off its scheduled path from Kuala Lumpur, the Malaysian capital, to Beijing on March 8 and dropped off civilian and military radar, no trace of the plane has been found. In the past week, searchers have focused on several vast areas of the Indian Ocean hundreds of miles from Australia. A flotilla of ships from various nations has combed the water, and aircraft have conducted daily reconnaissance flights.
The Haixun 01 has been a regular member of the search flotilla for days and is one of at least eight Chinese vessels that have helped in the search, Australian officials said.
On Friday, search coordinators said the underwater phase of the hunt had begun with the addition of two military ships — one from Australia and the other from Britain — equipped with underwater sensor technology.