Pakistan faces a critical risk of yet more flooding in the next three days in its southern plains, as a major river threatened to burst its banks. Sindh province irrigation minister Jam Saifullah Dharejo today said the next two to three days are very critical and they will have to strictly monitor the situation in the towns near the mouth of Indus river, which will have exceptionally high levels. He said thousands of irrigation officials had been deployed to strengthen river barriers at high-risk spots near the teeming city of Hyderabad. Pakistan's chief meteorologist Arif Mehmood confirmed the risk remained high in the south, while waters had receded in hard-hit Punjab, Khyber Pakhtunkhwa and Kashmir provinces. The worst natural disaster in the country's history has already affected 20 million people in nearly a month of flooding triggered by heavy monsoon rain, and left 1,500 dead by official count. Five million people have been made homeless across the country. Presidentent Asif Ali Zardari has warned the nation could take years to recover.