JAKARTA: Indonesia issued a tsunami warning on Friday, urging people to evacuate to higher ground after an earthquake of magnitude 6.8 struck off the coast of its island of Sulawesi.

Indonesia suffered its highest death toll in natural disasters in more than a decade last year, following two major tsunamis and several earthquakes, with more than 3,000 killed in Palu, also in Central Sulawesi, the site of Friday's earthquake.

"It is clear that the quake has tsunami potential," said geophysics agency spokesman Taufan Maulana. Residents are advised to evacuate as soon possible."

The agency is monitoring for high waves as the quake had the potential to trigger a tsunami, it added.

"The first wave may not be the biggest," it said in a statement.

There were no immediate reports of damage or casualties from the quake, which hit 280 km (174 miles) south of the province of Gorontalo at a depth of 43 km (27 miles), the agency added.

The quake was "strong and long lasting," Gina Saerang, a resident of Manado, the capital of North Sulawesi province, several hundred kilometres from the epicenter, said on social media.