The Indonesian Meteorology and Geophysics Agency warned Thursday the possibility of aftershocks following Sunday's 8.7-magnitude quake off Sumatra island that triggered a tsunami and claimed over 45,000 lives in Aceh.

The possible aftershocks are estimated to measure within the range of 4 to 6.2 on the Richter scale, agency head Gunawan Ibrahim said in a statement.

"Another tsunami is less likely to appear but residents in the area (Aceh) must remain vigilant," he said.