At least 26 people, including children, were killed as heavy rain lashed southern Indian state of Kerala since Friday, triggering landslides and floods, local media reported on Sunday.

Reports said deaths were found from three regions in the state - 13 were reported from Kottayam, nine from Idukki and four from Alappuzha district.

Indian Prime Minister Narendra Modi has offered condolences to the victims' families.

"It is saddening that some people have lost their lives due to heavy rains and landslides in Kerala. Condolences to the bereaved families," Modi tweeted.

Modi said he has discussed the situation with Kerala's chief minister. "Authorities are working on the ground to assist the injured and affected. I pray for everyone's safety and well-being," he added.

India's National Disaster Rescue Force, defense forces, and locals are continuing rescue and relief operations.

Meteorological department predicted that Kerala will continue to experience light to moderate rainfall until Monday, with further reductions expected thereafter.