Malaysia Airlines' missing jet transmitted its location repeatedly to satellites over the course of five hours after it disappeared from radar, people briefed on the matter said, as searchers zeroed in on new target areas hundreds of miles west of the plane's original course.

The satellites also received speed and altitude information about the plane from its intermittent "pings," the people said. The final ping was sent from over water, at what one of these people called a normal cruising altitude. They added...