* Buildings shake in flu-hit capital, hundreds evacuated

* Woman reported dead of heart attack near epicenter

* Magnitude revised down to 5.6 from 6.0 (Adds woman's death, Mexico City detail, quote)

By Cyntia Barrera

MEXICO CITY, April 27 (Reuters) - A 5.6 magnitude earthquake hit southern Mexico on Monday, shaking buildings far away in Mexico's flu-hit capital, but there were no major reports of deaths or damage.

A woman died of a heart attack near the quake's epicenter in the southern state of Guerrero, home to the Pacific coast resort of Acapulco, officials said, but there were no other casualties reported.

"It felt really strong here. There's been no one hurt or killed ... we're monitoring the situation in the area," said Marcos Gonzalez, a civil protection official in the city of Chilpancingo near the epicenter.

The tremor was felt in Mexico City, around 150 miles (240 km) away, and hundreds of people evacuated buildings. Most of them wore surgical face masks as protection against a swine flu outbreak that has killed up to 149 people in Mexico.

The U.S. Geological Survey revised the quake's magnitude down to 5.6 from 6.0 initially. Quakes of magnitude 5.6 are classified as moderate, capable of causing slight damage to buildings.

There was no major damage in Mexico City, a sprawling metropolis of around 20 million people, many of whom are old enough to remember a devastating 1985 earthquake that killed thousands of people.

"It was quite strong. I was eating a sandwich in a cafe and my table started shaking," said Luis Fernandez, 35, a lawyer who was sitting with a crowd of evacuees in the city center. "But it wasn't that bad, I stayed and finished my coffee."

The tremor hit as many people in the city were huddled at home because of the flu outbreak, which has grown into a major global health scare after infecting people in the United States and Europe.

Office workers raced outside after the quake, but were visibly anxious about finding themselves in a crowd. "I'm a bag of nerves," said cellphone executive Xochitl Cortez, 33.

The quake briefly jolted the Mexican peso, already battered on Monday by the flu outbreak.

Mexico's health minister, Jose Angel Cordova, said the flu outbreak was suspected to have killed 149 people in the country and the number of cases was seen rising. (Additional reporting by Catherine Bremer and Anahi Rama)

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