By Ainur Rohmah

TUBAN, Indonesia

A magnitude 6.1 earthquake hit the Flores Sea off Indonesia on Wednesday, but no tsunami alert was issued.

National Disaster Management Agency spokesman Sutopo Purwo Nugroho told Anadolu Agency that the temblor struck at around 2.39 a.m. (1939GMT Tuesday) while residents of nearby islands would have been sleeping.

The quake hit 105 kilometers (65 miles) northwest of East Flores Regency in East Nusa Tenggara province at a depth of 537 kilometers.

"Until now there has been no reports of damage and casualties," Nugroho said.

According to the head of the earthquake and tsunami mitigation division at the Meteorology, Climatology and Geophysics Agency, the impact of the tectonic earthquake had not been strongly felt due to the depth of its epicenter.

"Although this earthquake is classified as a strong earthquake, fortunately the quake has the type of deep hypocenter which [resulted in] no potential damage and no tsunami potential," Daryono, who like many Indonesians uses one name, told Anadolu Agency.

Indonesia lies within the Pacific’s "Ring of Fire", where tectonic plates collide and cause frequent seismic and volcanic activity.

In June, a magnitude 6.5 tremor damaged buildings in western Sumatra Island, with its shocks reportedly felt in parts of Singapore and peninsular Malaysia to the north.

On Dec. 26, 2004, a 9.1-magnitude earthquake struck the eastern coast of Sumatra, causing a tsunami that killed around 230,000 people as it tore along the coasts of Sri Lanka, India, Malaysia, Indonesia and Thailand.