Feb. 26 (Bloomberg) -- An earthquake measuring 6.4 hit near the Indonesian island of Sumatra, the third to strike the region in about 12 hours, the U.S. Geological Survey said. It may have generated a local tsunami, according to another U.S. agency.

The quake, which struck the Kepulauan Mentawai region at 4:02 a.m. local time at a depth of 35 kilometers (21.7 miles), was earlier reported by the USGS as a 6.9 magnitude temblor. There were reports of ``moderate'' shaking, the agency said on its Web site.

The U.S. Pacific Tsunami Warning Center and the Japan Meteorological Agency, which both measured the quake at 6.6, said in e-mailed alerts there was a ``very small possibility'' of a ``destructive local tsunami'' in the Indian Ocean.

A 7.2 magnitude earthquake struck at 3:36 p.m. local time yesterday and a temblor measuring 6.7 hit early today. There were no immediate reports of damage or casualties from those quakes, Indonesia's Meteorology and Geophysics Office said.

There have been hundreds of earthquakes in Indonesia since a 9.1 temblor in 2004 caused a tsunami that swept across the Indian Ocean, devastating coastal communities and leaving more than 220,000 people dead or missing in Indonesia, Sri Lanka, India, Thailand and other countries. The Indonesian archipelago lies in a region where tectonic plates are constantly shifting.

Yesterday's quake hit an area 165 kilometers southwest of Muko-muko, in Bengkulu province, at a depth of 10 kilometers, the Indonesian agency said.

An earlier tsunami warning was lifted, the Indonesian office said. The temblor sparked panic in Bengkulu and the west of Sumatra, sending people into the streets, Jakarta-based ElShinta radio reported. Tremors also rocked buildings in downtown Singapore, located 587 kilometers from the epicenter.

To contact the reporter on this story: Michael Heath in Sydney at mheath1@bloomberg.net.

Last Updated: February 25, 2008 19:04 EST