MOMBASA (Reuters) - The death toll from landslides in northwestern Kenya triggered on Saturday by unusually heavy rains has risen to at least 56 people, a local official said.

The downpour began on Friday in West Pokot County, which borders Uganda, and worsened overnight, causing flooding and mudslides that swept away four bridges and left villages inaccessible by road.

Samuel Poghisio, a senator from the county, told Reuters by phone on Sunday that 56 people were confirmed dead and an unknown number were missing. By Saturday afternoon, local officials had reported 36 dead.

“Rescue operations are frustrated by more rain and fog,” Poghisio wrote in a text message, adding that police helicopters were struggling to reach the flooded areas.

Kenya’s president on Saturday deployed rescue personnel from agencies including the army and the police to try and prevent the “further loss of lives”.

Researchers have warned that warming oceans are causing unpredictable weather patterns in East Africa.

Heavy rains and floods have killed more than 50 people and forced hundreds of thousands of people from their homes in the region since October, aid groups said earlier this month.

Kenya is experiencing a heavier than usual rainy season, the Kenya Meteorological Department said in early November.