The tremor was centred in O'Higgins Region, some 140km south of Valparaiso city, where the inauguration ceremony took place.

In Constitucion, which was heavily damaged in the 8.8-magnitude quake on February 27, residents scrambled for the hills after the navy issued a tsunami alert, but it was later lifted, except for Easter Island, where it remained in effect.

There were no reports of damages, injuries or fatalities, said emergency officials.  

President Pinera cancelled his party for foreign guests who were invited to attend the inauguration ceremony and flew to the quake zone.

He called on local residents to keep calm and vowed to take immediate action to overcome the aftermath of the recent earthquake that killed about 500 people and left thousands homeless.

The US Geological Survey initially estimated the largest aftershock's magnitude at 7.2, but later revised it down to 6.9. It was followed by more tremors, the biggest of which had a magnitude of 6.7.