A moderate earthquake has been detected at a nuclear test site in North Korea, signaling a possible nuclear test, seismologists say. (more The moderate earthquake, at 10 a.m. local time on Wednesday, was centered at a nuclear test facility northwest of Kilju in the North's northern region. The U.S. Geological Survey put the magnitude at 5.1. There was no immediate confirmation on whether a nuclear test had been carried out, but past nuclear tests caused seismic readings that matched Wednesday's event.

James Valles reporting