Thousands of devotees offered prayers at the historic Mangala Devi temple, situated inside the Periyar Tiger Reserve on the Kerala-Tamil Nadu border, during the annual Chitra Pournami festival on Friday.

The ancient temple, believed to be over 1,000 years old, is open to devotees only on the full moon day of the Chitra month every year and witnessed a heavy influx of pilgrims from both states, officials said.