A 6.4-magnitude
earthquake struck
Puerto Rico before dawn on Tuesday, and was followed three hours later by an aftershock measuring 6.0.

Puerto Rico's power authority said on
Twitter that one of the country's main power plants, which sits near the epicenter, had been damaged, but officials expect to restore power to the island later Tuesday.
A
tsunami alert was issued for Puerto Rico and the U.S. Virgin Islands after the initial quake, but was later canceled.