Flood-stricken Pakistan urgently needs more international aid to combat potential instability and extremism, influential U.S. Senator John Kerry said, as hunger and disease threaten millions of victims.

In a commentary in the International Herald Tribune, Kerry, who heads the Senate Foreign Relations Committee, said that the international community was not meeting its responsibilities towards Pakistan, where floods have killed more than 1,600 people and left at least 6 million homeless.

The danger of the floods extends beyond a very real humanitarian crisis, Kerry wrote in Monday's edition.

A stable and secure Pakistan, based on democracy and the rule of law, is in all of our interests. Pakistan has made enormous strides in combating extremism and terrorism -- at great sacrifice. But its ability to keep up the fight requires an effective response to this crisis.

Pakistan has struggled with its response to the massive flooding, which has left one-fifth of the country under water, an area the size of Italy. Some Pakistanis have grown increasingly angry with the sluggish government response, and are turning to Islamist charities, some of them tied to militant groups.

We don't want politicians. We want the Islamic groups in power. The government just steals, said Haidar Ali, a college student in the devastated Swat Valley, whose life has been reduced to laying bricks all day in stifling heat.

The United States worries that the battle against Islamist militants may have become harder in Pakistan, with a weakened administration battling economic meltdown and public fury.

But in south Punjab, there is no evidence people are looking to the Islamists to solve their problems. No one interviewed expressed any interest in politics, nor indeed in any subject, beyond getting help from whoever was prepared to provide it. There also was no evidence of Islamist groups out in force.

Poor, rural and fatalistic, the people were more inclined to be resigned to their fate.

God will decide our future. We don't know, said 80-year-old Malik Mahmood.

The floods began in late July after torrential monsoon downpours over the upper Indus basin in the northwest.

WATERS RECEDING

In Jampur, in southern Punjab, about 500 km southwest of Islamabad, waters have begun to recede but thousands of people still live in relief camps.

In about two weeks' time, when the river returns to normal, that's when we expect movement in the population (to go home), Brigadier Zahid Usman told Reuters.

Further south in Thatta, in Sindh, the flooding that threatened the city of 300,000 has been largely stanched, said Saleh Farooqi, director general in Sindh for National Disaster Management Authority, but Sajwal to the east is under water.

There has not been a substantial relief but things have improved, he said. Water is still flowing but the speed and levels are reducing. It will take another four to five days for things to improve further.

The death toll from the flooding was expected to rise significantly as the bodies of the many missing people are found. There is no official estimate of the number of missing because mass displacements have made accounting for them almost impossible.

Kerry is a co-sponsor of the Kerry-Lugar-Berman aid package, which would funnel $7.5 billion (4.8 billion pounds) over five years in civilian development money to Pakistan. Last week, the head of the United States Agency for International Development said $50 million from the package would be diverted to immediate flood relief.

The United Nations said aid workers were increasingly worried about disease and hunger, especially among children, in areas where even before the disaster acute malnutrition was high.

The receding floods have left behind huge pools of stagnant water, which in turn are breeding disease. U.N. officials say an estimated 72,000 children, affected by severe malnutrition, were at high risk of dying.

(Additional reporting by Myra MacDonald and Kamran Haider in JAMPUR, Faisal Aziz in Karachi; Editing by Sanjeev Miglani and Alex Richardson)

Pakistan