An earthquake with a preliminary magnitude of 6.7 struck western Ecuador early Wednesday, the U.S. Geographical Survey said, likely a huge aftershock from last month's deadly tremblor, NBC says.

The quake's epicenter was 36 miles south of Esmeraldas at a depth of about seven miles.

A destructive Pacific-wide tsunami was not expected, the Pacific Tsunami Warning Center said in a statement.

Ecuador's interior ministry said teams had been deployed on the ground deployed to assess damage and report back. The president, Rafael Correa, tweeted from Quito that there were no reports of damage, NBC says.

The quake struck the same side of the country as 7.8-magnitude earthquake last month, Ecuador's worst in nearly seven decades. That temblor killed more than 650 people, including one American, and injured around 16,600.

Further tremors were expected for several weeks after that quake, which destroyed 7,000 buildings and left more than 25,000 people living in shelters.