A baby girl died in northern Chile on Friday, putting the death toll of a massive 8.2-magnitude earthquake this week to seven, authorities said.

The six-day-old newborn died of heart failure after sleeping in a tent with her mother since Tuesday in Alto Hospicio near Iquique.

Life was gradually returning to normal in the worst-hit region on Friday as water and electricity supplies were restored to most homes. But soldiers were guarding supermarkets and gas stations to prevent looting as people lined up for water, food and gasoline.

The 8.2-magnitude quake destroyed houses and buildings and cut off electricity in Chile's northern towns late Tuesday, sparking tsunami warnings along its northern Pacific coast.

Chilean President Michelle Bachelet has said her country would seek "a safe return to normalcy" after the powerful quake.