PUERTO RICO (CBSMiami/AP) – President Donald Trump has approved an emergency declaration in Puerto Rico following a magnitude 6.4 earthquake that struck Tuesday morning.

The declaration authorizes FEMA to coordinate all disaster relief efforts and provide appropriate assistance for required emergency measures to save lives and protect property.

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The Federal Emergency Management Agency announced aid has been made available to supplement local response efforts.

Cars, cots and plastic chairs have became temporary beds for hundreds of families who lost their homes in the strongest quake to hit Puerto Rico in more than 100 years.

The quake killed one person, injured nine others and knocked out power across the U.S. territory, and a majority of Puerto Ricans remained without electricity Wednesday.

Nearly 750 people were staying in government shelters in the island’s southwest region as Gov. Wanda Vázquez declared a state of emergency and activated the National Guard. She also pleaded with residents to remain clam and prepare for aftershocks.

The quake was the strongest and likely the most damaging of hundreds of temblors that have struck the island since December 28.

A collapsed business is seen after an earthquake hit the island in Guanica, Puerto Rico on January 7, 2020. (Photo by RICARDO ARDUENGO/AFP via Getty Images)

Terrified of sleeping indoors as aftershocks continue, neighbors put mattresses in their front yards while others spent the night Tuesday under white tents and tarps.

Riko Gonzalez and his parents were asleep in their home in Yauco, near Indios, when the quake struck. They scurried out of the house as dishes tumbled to the kitchen floor, he said.

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Hundreds of aftershocks have hit the area in the past few days.

“People are afraid to go to bed, to then be woken up to worse earthquakes than the day before,” Gonzalez said.

Much of Puerto Rico is still without power Wednesday as engineers work to restore it in phases, however, it has been restored in most hospitals, and crews are working to fully restore it by the weekend.

Classes won’t resume across the island until crews inspect all schools and confirm buildings are safe for students, education officials announced.

The earthquakes come after Hurricane Maria devastated the US territory in September 2017. Many in southern Puerto Rico said the earthquakes’ damage was worse.

“There’s no warnings for this,” Puerto Rico Police Commissioner Henry Escalera said of the earthquakes. “A hurricane gives us time to plan ahead.”

When asked what concerns him the most about the quakes’ aftermath, he said, “That homes will not be safe to live in and the possibility of a collapse that will cause a person’s death or serious injuries.”

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(© Copyright 2020 CBS Broadcasting Inc. All Rights Reserved. The Associated Press and CNN contributed to this report.)