Much of the nearly completed four-story parking garage at the Mexicali Civic Center lies in ruins after the magnitude 7.2 earthquake.

Much of the nearly completed four-story parking garage at the Mexicali Civic Center lies in ruins after the magnitude 7.2 earthquake. (The Los Angeles Times)

LOS ANGELES -- A moderate aftershock rattled northern Baja California Friday, days after the area was struck by a deadly magnitude-7.2 earthquake on Easter Sunday.

The magnitude-5.1 aftershock struck 36 miles south of Mexicali at 4:05 p.m. Friday. No damages have been reported, but the area continues to suffer from numerous aftershocks.

Just a day earlier, another magnitude 5.3 aftershock struck about 30 miles south of Mexicali around 9:45 a.m Thursday, causing one building's roof to collapse and minor damage to other buildings

Governor Arnold Schwarzenegger toured the U.S border city of Calexico Thursday morning, but his spokesman says he left before the aftershock.

On Monday, Schwarzenegger proclaimed a state of emergency for Imperial County, which suffered the brunt of the U.S. damage from the Easter Sunday's quake.

At least two deaths and some 100 injuries are being blamed on the powerful temblor. Both deaths occurred in Mexico.

A 94-year-old man was killed when a wall collapsed in his home in the city, and homeless man died when the abandoned home he was living in collapsed in a farming community, Mexican officials said.

Civil protection authorities said Sunday that another man died when he ran into the street in panic and was struck by a car, but the government did not count him among the earthquake victims Monday.

There were no reports of U.S. deaths. A spokeswoman for Imperial County's emergency operations said two people were injured and one was listed in critical condition. No further details were provided.

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The declaration by Gov. Schwarzenegger will free up state resources to aid the recovery effort.

Businesses in Calexico -- the U.S. area hit hardest -- were guarded by police Sunday night after the quake damaged pre-war buildings not updated to handle strong quakes, Calexico police Lt. Gonzalo Gerardo said.

"Downtown is going to remain closed until further notice," he said.

By Monday morning, 80-percent of the historic downtown area had been red tagged.

City Manager Victor Carrillo said the damage would easily total millions of dollars.

City officials, under a state of emergency, asked residents to limit water use to essential bathing, cooking and washing.

Mexicali was the hardest hit area overall, where reports included structural damage, broken windows, leaking gas lines, loss of water services, and loss of electricity in portions of Northern Mexico.

At least 45 businesses and dozens of homes were destroyed there.