Jakarta - Indonesian authorities issued a tsunami warning after a powerful 7.7-magnitude earthquake struck off Sulawesi shortly after midnight Sunday, seismologists said.Indonesia's National Meteorology and Geophysics Agency (BMG) said the quake struck at about 00:02 am Monday (1702 GMT Saturday, with its epicentre about 130 north-west of Gorontalo in North Sulawesi.   read more »