Fever and diarrhea are spreading among victims of the worst flooding in Pakistan

Fever and diarrhea are spreading among victims of the worst flooding in Pakistan in decades, officials said Friday amid warnings that storm waters were again surging south along swollen rivers, threatening more destruction.

The floods have affected 14 million people and about a quarter of the country, overwhelming an already weak government coping with crushing economic conditions and attacks by al-Qaida and Taliban militants. Around 1,500 people have been killed since the torrents began more than two weeks ago.

"The crisis facing Pakistan is not only enormous, it's still unfolding," U.N. refugee agency spokesman Adrian Edwards said. "There continues to be massive destruction as the bloated rivers flow southwards across the plains and the crisis in our view will not be over when the flooding recedes."

Pakistani villagers who fled their flood-affected areas arrive in Jaffarabad, Pakistan on Friday, Aug. 13, 2010. Fever, stomach problems and skin diseases are spreading among Pakistani flood victims, officials said Friday, adding another dimension of danger to a crisis that could get even worse, with the U.N. warning that dams in the south may burst. (AP Photo/Fida Hussain)

Pakistani flood affected villagers sit in the rubble of their houses in Aza Kheil, Pakistan on Friday, Aug. 13, 2010. International aid for Pakistani flood victims is coming in slowly compared to other recent disasters despite the massive number of people affected and the potential for dire economic consequences in a country key to Western hopes in the fight against Islamist extremists. (AP Photo/Mohammad Sajjad)

Pakistani villagers wave to a Pakistan Navy helicopter approaching a flooded area of Ghaus Pur near Sukkur, in Pakistan's Sindh province, Wednesday, Aug. 11, 2010. (AP Photo/Shakil Adil)

Villagers wade through flood waters after having evacuated their homes on August 10, 2010 in the village of Baseera near Muzaffargarh in Punjab, Pakistan. The rivers Indus and the Chenab are in fear of having their levies broken which would cause catastrophic flooding across Punjab and Sindh provinces. (Photo by Daniel Berehulak/Getty Images)

A Pakistani villager's house was submerged by flood water near Dera Ghazi Khan, Pakistan

A flood-affected man sits over the debris of his house collapsed by flooding in Nowshera, northwest Pakistan, Monday, Aug. 9, 2010. (AP Photo/B.K. Bangash)

A Pakistani villager stands outside what is left of homes washed away by heavy floods in Charsadda, northwest Pakistan, Monday, Aug. 9, 2010. (AP Photo/B.K. Bangash)

Pakistani villagers chase to relief supplies dropped from an army helicopter in a heavy flood-hit area of Mithan Kot, in central Pakistan, Monday, Aug. 9, 2010. (AP Photo/Khalid Tanveer)

Houses are half submerged in floodwater in Mithan Kot, in central Pakistan, Monday, Aug. 9, 2010. (AP Photo/Khalid Tanveer)

This aerial view shows a flood-hit area of Kot Addu, Pakistan on Wednesday, Aug. 4, 2010. Floodwaters ravaged hundreds of villages in Pakistan's main province of Punjab, destroying homes, soaking crops, and threatening more lives. Aid workers warned that bloated rivers would soon surge into the country's south, prompting more evacuations. (AP Photo/Khalid Tanveer)

A boy takes a moment to rest after salvaging belongings from his flood destroyed home on August 4, 2010 near Nowshera, Pakistan. (Photo by Daniel Berehulak/Getty Images)

A flood-stricken Pakistani family carries belongings retrieved from their home that was destroyed by heavy monsoon rains on the outskirts of Peshawar, Pakistan,