BRASILIA Brazil's government is preparing a task force to provide emergency assistance to inhabitants in the Amazon region hit by a severe drought that has impacted the rivers that are their life support, Environment Minister Marina Silva told Reuters.

Low river levels and hotter waters have killed masses of fish seen floating on river surfaces, contaminating the drinking water, she said.

"We have a very worrying situation. This record drought has disrupted river transport routes threatening food and water shortages, and a large fish mortality is already beginning," she said in an interview.

The federal task force would be airlifted by the Air Force to the states of Amazonas and Acre with water, food, medicines and other resources, she said.

Some 111,000 people have been affected in a region where a large part of the population's protein comes from fishing, which will be suspended for some time, she explained.

The government also allocated 140 million reais to dredging rivers and ports in the region to keep transport flowing when water levels drop, Silva said.

The drought in the Amazon, like the flooding in the south of Brazil, are the result of the El Niño phenomenon, which warms the surface water in the Pacific Ocean, and this year the impact has been greater than normal, weather experts say.

Silva said this was the effect of a periodic El Niño mixing with changes in weather patterns brought by global warming.

"We are seeing a collision of two phenomena, one natural which is El Niño and the other a phenomenon produced by humans, which is the change in the Earth's temperature," she said.

Worsened by climate change, this combination has caused drought not seen before in the Amazon and "is incomparably stronger and could happen more frequently," she warned.

(This story has been corrected to fix the number of affected to 111,000 in paragraph 5)

(Reporting by Lisandra Paraguassu, writing by Anthony Boadle; Editing by Alistair Bell)