马航班机在失联后数小时内向卫星发送电子脉冲信号

The search for a missing Malaysian jetliner expanded toward the Indian Ocean on Friday, as new evidence emerged that the jet may have traveled for hours after it vanished.

Speaking anonymously, U.S. officials briefed on the investigation said the Boeing 777 sent automated electronic messages to satellites several hours after it disappeared from civilian radar Saturday.

The officials said the communications satellites detected faint messages, known as pings, which attempted to relay regular maintenance and other data about the plane's condition.

It is not clear whether the messages can provide information on the plane's location. It is also not clear whether the plane was in the air at the time the messages were sent.

Ships and planes from over a dozen countries have been searching for six days for the Malaysia Airlines plane and its 239 people on board, who were headed from Kuala Lumpur to Beijing.

The initial search focused on the Gulf of Thailand, where the airliner was last spotted by civilian radar. The Malaysian military has since said it may have tracked the plane hundreds of kilometers away, across the Malaysian peninsula in the Strait of Malacca.

On Thursday, White House spokesman Jay Carney said "an additional search area may be opened" in the vast Indian Ocean. It is the world's third largest ocean and is significantly deeper than the other search areas.预计搜寻马来西亚航空公司失联班机的范围星期五将扩大至印度洋，新证据显示这架班机在失联后可能继续飞行了几小时。

未透露姓名的美国官员在介绍调查情况时说，这架波音777客机上星期六从民用雷达屏幕上消失后的几小时内，自动向卫星发送电子信号。

有关官员说，通信卫星接收到微弱的电子脉冲信号，这种信号的设计用途是通报飞机的一般维护状态以及其他数据。

目前还不清楚这些电子脉冲信号能否提供有关失联班机所在位置的信息，而且也不清楚班机在发送信号时是否处于飞行状态。

来自12个国家的船只和飞机的搜寻已经持续了六天。这架班机载有239人，原定从吉隆坡飞往北京。

最初的搜寻集中在泰国湾，这架班机在那里从民用雷达屏幕上消失。马来西亚军方说，可能探测到这架班机偏离航线数百公里，跨越马来西亚半岛到马六甲海峡。

白宫发言人卡尼星期四说，可能要在印度洋广大海域展开新的搜寻行动。印度洋是世界第三大洋，水深远远超过已经搜寻过的海域。