Government officials in the Indian Ocean island countries of Madagascar and Mauritius issued warnings of a possible tsunami following an earthquake measuring over 8.0 on the Richter scale struck Monday off the Indonesian island of Sumatra.

In Madagascar, weather and rescue services issued alerts for the entire east of the country, officials said. The director of the national meteorological service Alain Razafimahazo had a plan to go on national radio and TV to warn the population.

On Mauritius, the national weather service said it sent out tsunami alerts to the coastal regions as well as the islands of Rodrigues and Agalega.

Rajesh Bhagwan, the Mauritian environment minister, said the population was asked "to take all precautions" even though the epicenter was about 4,000 kilometers away.

The earthquake quake occurred at 23:15 local time (1615 GMT) some 90 kilometers southeast of the island of Sinabang, which lies off the southern coast of Indonesia's Sumatra island.

The US Geological Survey said the earthquake measured magnitude8.7 while Japan's Meteorological Agency measured it at magnitude 8.5.

Robert Cessaro, a US expert with the Los Angeles-based Pacific Tsunami Warning Center, told CNN that the earthquake was likely to have produced a tsunami probably in the form of a beam of energy heading to the Indian Ocean island of Mauritius.

India, Malaysia, Sri Lanka, Thailand and Indonesia also issued tsunami alerts after Monday's earthquake. But Thailand called off the alert a few hours later.

More than 273,000 were killed on December 26 last year when a similar earthquake struck off Indonesia's Banda Aceh city and caused a massive subsequent tsunami.