The death toll from flash floods hammering northeast Brazil rose to 20 on Monday, as the governor of Bahia state declared it the worst disaster in the state�s history and rescuers braced for more rain in the coming days.

Much of Bahia, home to about 15 million people, has suffered from intermittent flooding for weeks, after a long drought gave way to record rains.

Flooding in some areas intensified late on Christmas Eve and early on Christmas Day after a pair of dams gave way sending residents scrambling for higher ground.

Authorities have confirmed that 72 municipalities are in state of emergency.

Rescue workers patrolled in boats around the city of Itabuna, in southern Bahia, plucking residents from their homes, including some who escaped through second-floor windows.

Manfredo Santana, a lieutenant-colonel in Bahia�s firefighting corps, told Reuters that emergency workers had rescued 200 people in just three nearby towns. The heavy currents of the swollen Cachoeira River complicated rescue efforts.

With this volume of water even manoeuvrability with jet skis was difficult. It is difficult to reduce risks for the pilot or the victim being rescued, there is no use on simply getting into the inflatable boat and not being able to do the rescue safely, said Santana.

According to local media, authorities are monitoring an additional ten dams for any signs they may collapse.