A 5.6-magnitude earthquake has shaken buildings in Puerto Rico and the Dominican Republic but caused no damage.

The quake happened early Saturday in the Mona Passage between the U.S. Caribbean territory and the island of Hispaniola, which the Dominican Republic shares with Haiti.

U.S. Geological Survey geophysicist Randy Baldwin said the tremor was not an aftershock of the devastating Jan. 12 earthquake that killed an estimated 300,000 people and left millions homeless in Haiti.

A couple of tremors reported earlier this week in Haiti have been identified as aftershocks, however.