NAIROBI, March 15 (Xinhua) -- Heavy rain that started early Thursday flooded Kenya's Nairobi, cutting off some key city roads and affecting flow of vehicles at large.

Poor drainage system has been blamed for worsening the mayhem and traffic jams in the wake of the heavy rain, which prompted motorists and commuters to adopt survival strategies to reach their work stations.

Nairobi Traffic Police commander Joshua Omukata appealed to motorists to exercise caution and be patient while on the roads.

Omukata said traffic flow is extremely slow and a number of vehicles had been stuck on the roads.

"There is poor drainage at large and after the rains we have problems. Most roads are affected by the floods," he said.

The police commander said more traffic personnel were mobilized to help manage the situation.

Other police officers advised motorists, who did not need to travel, to shelve their plans.

"If you need not travel, avoid it for now. We have a situation where most roads are flooded and this may affect you," said a police officer based at a control center.

The Kenya Meteorological Department has warned there will be heavy rains in the coming days.