Disaster agency spokesman Sutopo Purwo Nugroho said in a television interview there are "many victims".
The U.S. Geological Survey said Friday the natural disaster at a depth of 11 miles (18 kilometers) was centered about 19 miles (30 kilometers) north of the central Sulawesi town of Donggala.
The warning was lifted within the hour, but officials asked people to remain on the alert as a number of moderate aftershocks hit. An Indonesian official said there were "many victims".
Donggala is a city of about 270,000 people, while the nearby city of Palu is home to about 330,000 people.
"The quake and tsunami caused several casualties. while initial reports show that victims died in the rubble of a collapsing building", National Disaster Mitigation Agency spokesman Sutopo Purwo Nugroho told reporters.
"All national potential will be deployed, and tomorrow morning we will deploy Hercules and helicopters to provide assistance in tsunami-affected areas". "The situation is chaotic, people are running on the streets and buildings collapsed", she said.
Patients are evacuated from a hospital following a strong quake in Poso, central Sulawesi, Indonesia. "There is a ship washed ashore".
Confirmado: la serie de Luis Miguel tendrá una segunda temporada
Y la historia, en este caso, se centrará en algunos escándalos y en varios de los romances más famosos del artista. Y como los productores querían asegurarse de que Luismi aceptara, la producción decidió triplicar el número .
People survey a building partially damaged by natural disaster in Poso, Central Sulawesi.
The quake has been followed by strong aftershocks and a local disaster official tells The Associated Press that many houses have collapsed.
United Nations spokesman Stephane Dujarric said United Nations officials were in contact with Indonesian authorities and "stand ready to provide support as required".
The earlier quake destroyed some houses, killing one person and injuring at least 10, authorities said.
"All the things in my house were swaying and the quake left a small crack on my wall", Donggala resident Mohammad Fikri said by telephone.
In December 2004, a massive magnitude 9.1 natural disaster off Sumatra in western Indonesia triggered a tsunami that killed 230,000 people in a dozen countries.
Indonesia sits on the Pacific Ring of Fire, an area of great seismic and volcanic activities, where some 7,000 earthquakes, mostly moderate, are recorded each year.
A series of earthquakes in July and August killed almost 500 people on the holiday island of Lombok, hundreds of kilometers southwest of Sulawesi.