A Moderate 5.6-magnitude earthquake hit off Indonesia's Sumatra island on Sunday, but no casualties, damage or a possible tsunami reported immediately, according to official sources.
  
The quake struck at 8:28 a.m. local time (0128 GMT) was centered under the Indian Ocean, about 55 km northwest of Gunung Sitoli, the main town on Nias island, the Meteorology and Geophysics Agency of Indonesia said, adding "the tremor was strongly felt, but did not cause any damage and even a tsunami."
  
The quake, whose epicenter was 18 km under the Earth's surface, was only felt on the island, the Agency said. 
  
Nias is located about 1,350 km northwest of the Indonesian capital, Jakarta, which was hit hard by the December 2004 earthquake and tsunami.