BOSTON -- For the second time this month, an earthquake has hit Massachusetts.

NewsCenter 5 received numerous calls from people in the Groton, Westford and Littleton area. Residents said that they heard what sounded like a loud boom or explosion. Some said that they felt their homes shake.

Video: Quake Wakes Residents

The U.S. Geological Survey confirmed that an earthquake measuring 2.5 hit the region at about 1:30 a.m. Residents in Westford and Littleton also said that they heard rumblings at about 6:05 a.m.

"It reminded me of back in the military, and it felt like the guns going off right in the front yard. It was a big, loud bang," resident Hank Plaistek said.

Police received a number of 911 calls from concerned residents. The epicenter of the quake was near Littleton's common.

"(It was) a big relief. When you start getting phone calls like that for an explosion, we have a major highway running through here with all sorts of hazardous materials running up and down the highway," Littleton Fire Department Chief Stephen Carter said.

Earlier this month, a quake measuring 1.8 on the Richter scale rattled homes in Amesbury and Merrimac. Officials said that quake was a late aftershock of an earthquake from 1727 in Newburyport.