The USGS says an earthquake with a magnitude of 7.4 hit southwest Mexico today.

The United States Geological Survey says it was 6.2 miles deep and about 120 miles east of Acapulco.

We'll have more on this story as it develops.

Update at 3:54 p.m. ET. Back To Normal:

NPR's Jason Beaubien, reporting from the Zocalo area of Mexico City, says officials report no deaths and no major damage.

"And here in the capital," adds Jason, "things have just very quickly gone back to normal."

Update at 3:34 p.m. ET. Malia Obama Safe:

President Obama's oldest daughter Malia was on a school trip to Mexico when the earthquake struck.

ABC News reports that she is safe.

"In light of today's earthquake, we can confirm that Malia Obama is safe and was never in danger," the Michelle Obama's Communications Director Kristina Schake told the network in a statement.

Update at 3:30 p.m. ET. Revised To 7.4 Magnitude:

The U.S. Geological Survey has revised its estimate of the earthquake's strength again, to 7.4 magnitude. So the size has been downgraded twice — from the original 7.9 to 7.6 and now 7.4.

Update at 2:55 p.m. ET. Mexico Says Earthquake Was 7.8 Magnitude:

On his twitter account , President Felipe Calderón says Mexico's seismology agency says the earthquake measured 7.8 on the Richter scale. He adds, "There are still no reports of major damage."

Update at 2:50 p.m. ET. No Major Damage In Mexico City:

The mayor of Mexico City, Marcelo Ebrard, is reporting no major damage in his city. On his twitter account , Ebrard says they've inspected the central part of the city, the northern part of the city and there are no mayor damages.

The airport, Ebrard reports, is also operating normally.

Update at 2:43 p.m. ET. Felt Strongly In Acapulco:

CNN Español reports that the earthquake was felt strongly in Acapulco, too. It forced residents to the streets.

CNN also reports that slowly office workers in Mexico City are returning to their office towers.

Update at 2:38 p.m. ET. No Major Damages Reported Yet:

Mexican President Felipe Calderón just tweeted that "no major damages have been reported, according to a national seismologist."

Update at 2:32 p.m. ET. Mexico City Feels Strong Shaking:

Olivia Sanchez, a Mexico City resident, just told our Newscast unit that the earthquake shook the city very hard. She said that people are on the streets right now and the lights went off momentarily.

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