Islamabad , Pakistan ( CNN ) -- Intense rain and gushing flood waters threatened Wednesday to cause more misery in monsoon-bloated Pakistan , where 3 million people are already suffering . U.S. Secretary of State Hillary Clinton urged Americans to donate to relief efforts , saying that experience in post-earthquake Haiti showed that small donations can make a big difference . Pakistani Prime Minister Yousuf Raza Gilani appealed to residents to curtail expenditures for Ramadan feasts and upcoming independence day celebrations and contribute instead to help their desperate compatriots . As many as 1,500 people have died in Pakistan 's worst flooding in 70 years . Relief agencies were struggling to reach people who have lost everything to walls of water . Many were cut off after roads and bridges washed away . Thousands of others were people already displaced by violence in Pakistan and neighboring Afghanistan , according to the United Nations refugee agency . The flooding also washed away tens of thousands of homes , devastated livestock and swept away farm land . The United Nations High Commissioner for Refugees said it has distributed 10,000 tents so far , along with other relief supplies which have assisted some 50,000 people in Khyber Pakhtunkhwa and Balochistan provinces . Speaking to reporters in Washington , Clinton stressed the importance of U.S. assistance to Pakistan , a strategically important country whose relationship with Washington continues to be a work on progress . The Obama administration is looking to turn the natural disaster into opportunity , hoping a robust response to the crisis will help improve its poor image among a skeptical Pakistani public . A senior Pakistani military official told CNN that six U.S. helicopters landed at Ghazi airbase Wednesday near the village of Tarbela Ghazi , just north of Islamabad , to participate in the rescue and relief work . The United States has already committed $ 10 million in aid , and U.S. helicopters have airlifted flood victims and helped deliver critical supplies including temporary bridges and 300,000 halal meals , food that meets Islamic dietary law . `` We 've been working hard over the past year to build a partnership with the people of Pakistan , and this is an essential element of that partnership -- reaching out and helping each other in times of need , '' Clinton said . She urged Americans to use their cell phones to text the word `` SWAT '' to the number 50555 to make a $ 10 contribution to the U.N. refugee agency . The Pakistan Meteorological Department predicted more misery in the days ahead . As much as 2 inches of rain is forecast over the next two days for central Pakistan while scattered showers will continue to fall in the north . Rushing river waters could cause more flooding in downstream areas by this weekend , meteorologists said . In some areas , Pakistanis complained the government has been sluggish to respond . In a special emergency meeting Wednesday , Gilani said the government was doing all it could to address the crisis . People stranded in Tonsa Sharif and Dera Ghazi Khan were still waiting for government relief , reported CNN affiliate Geo TV . Meanwhile , limited access to clean water and poor hygienic conditions raised the threat of widespread acute respiratory infections , diarrhea and skin infections , said the medical group Medecins Sans Frontieres ( also known as Doctors Without Borders ) , which is supporting health units in Mandrakhel , Wadpaga , and Gulbela in the Peshawar district , and the Paddi Hospital in the Nowshera district . Collapsed bridges meant the medical teams were unable to reach the badly hit North Swat region . A case of cholera has been confirmed in Swat . CNN 's Reza Sayah and Elise Labott contributed to this report .
NEW : Secretary of State Clinton appeals for aid . NEW : Hillary Clinton says the crisis aid is essential part of building ties with Nowshera . As many as 1,500 people have been affected by monsoon rains and flooding . Some Americans say their government has been slow to respond .