MUZAFFARGARH Pakistan (Updated) - Pakistanis desperate to get out of flooded villages threw themselves at helicopters on Saturday as more heavy rain was expected to intensify both suffering and anger with the government. President Asif Ali Zardari may have made the biggest political mistake of his career by leaving for visits to Paris and London during the worst floods in 80 years. The disaster has killed more than 1,600 people and disrupted the lives of 12 million. Pakistan's agriculture-based economy, heavily dependent on foreign aid, has suffered a major blow. Heavy rains are expected to lash the country again raising the prospect that more houses and crops will be swept away. In the town of Muzaffargarh, near where rivers bloated with rain from as far away as Afghanistan and India merge with the Indus to flow south to the sea, army helicopters dropped packets of rice to people who had moved to higher ground to a cemetery. Some latched on to helicopter skids as the aircraft took off. An elderly man fought his way inside one. He looked down and wept. "Things are getting worse. It's raining again. That's hampering our relief work," said U.N. World Food Programme spokesman Amjad Jamal. Districts in southern Sindh province were on high alert on Saturday as the water surged down the Indus river basin.