The Pacific Tsunami Warning Center issued a tsunami warning, the highest level of a tsunami alert, for the entire Pacific region, including Hawaii and places as far away as Russia and Japan.
"We have information of high-altitude waves that could be seen in the following hours," Bachelet said. "We are evacuating people in lower areas to higher ground." California and Alaska are under a tsunami advisory.
"An earthquake of this size has the potential to generate a destructive tsunami that can strike coastlines near the epicenter within minutes and more distant coastlines within hours," the National Weather Service said in a statement.
USGS geophysicist Victor Sardina said several tsunami waves had come ashore along the Chilean coast; the largest was recorded at 9 feet near the quake's epicenter.
The earliest estimated arrival for a wave that could affect Hawaii was 12:46 a.m. local time (6:46 p.m. ET). But evacuations of coastal areas were to begin at 6 a.m. (12 p.m. ET).