(CNN) Seismic activity was detected Saturday near the site of North Korea's Punggye-ri nuclear site, but it is not known whether a nuclear test caused the development. The first sign Pyongyang has conducted a nuclear test is usually seismic activity. North Korea has one nuclear test site -- Punggye-ri. "This event occurred in the area of the previous North Korean nuclear tests," the USGS said. Saturday's detection comes at a time of rising tensions between the United States and North Korea, with North Korean dictator Kim Jong Un and President Donald Trump engaging in an escalating war of words.

Source: CNN September 23, 2017 11:39 UTC