SUKKUR, Pakistan - Disease outbreaks pose new risks to victims of Pakistan's worst floods in decades, aid agencies said on Friday, potentially hindering relief efforts.

The floods, triggered by torrential monsoon downpours, have engulfed Pakistan's Indus river basin, killing more than 1,600 people, forcing two million from their homes and disrupting the lives of about 14 million people, or 8 percent of the population.

Although the waters have receded in some areas, fresh rains could bring new destruction, and a health crisis would tax aid agencies already facing huge logistical challenges.