TANJUNG, Indonesia — The Indonesian island of Lombok was shaken by a third big earthquake in little more than a week on Thursday as the official death toll from the most powerful of the quakes increased to more than 300 people.

The strong aftershock, which the United States Geological Survey said had a magnitude of 5.9, caused panic, damage to buildings, landslides and injuries. It was centered in the northwest of the island and did not have the potential to cause a tsunami, Indonesia’s geological agency said.

The aftershock caused more trauma for Indonesians, said a spokesman for the national disaster agency, Sutopo Purwo Nugroho.

Wiranto, Indonesia’s top security minister, who uses only one name, told reporters that the death toll from Sunday’s magnitude 7.0 quake had risen to 319. The announcement came after an interagency meeting was called to resolve wildly different figures from various government offices.