SANTIAGO (Reuters) - A powerful 6.5 magnitude earthquake struck near the Chilean capital Santiago on Monday, the U.S. Geological Survey said.

The quake, which the USGS initially measured at a magnitude of 6.6, struck 30 miles north-northeast of the main port of Valparaiso, and 72 miles northwest of the capital Santiago at a depth of 16.1 miles, it said.

There were no initial reports of damage or injuries.

The USGS initially said the quake struck at a depth of 41.9 miles.

(Writing by Eric Walsh)