A state of emergency has been declared and 31 people told to leave their homes because of a wildfire threatening the Xgat'tem or Canoe Creek First Nation in central B.C.

The fire was discovered on Wednesday and exploded in size Friday from 600 hectares to cover 1,800 hectares near the Dog Creek Reserve, about 200 kilometres northwest of Kamloops.

Another 100 residents are also on evacuation alert.

Firefighters are now battling the blaze, which is believed to have been caused by lightning.