NEW YORK - An international human rights watchdog on Tuesday warned that severe shortages of food and medicine are creating "a humanitarian catastrophe" for thousands still trapped in fighting between Taliban and Pakistani troops in Swat region. THe New York-based Human Rights Watch demanded the Pakistani government immediately lift a week-long curfew that was preventing "hundreds of thousands" civilians from leaving the conflict zone and having access to food and medical supplies. "The government cannot allow the local population to remain trapped without food, clean water, and medicine as a tactic to defeat the Taliban," said Brad Adams, the group's Asia director. Nearly 2.4 million people have been displaced since May 2 when the military operations were launched. The Human Rights Watch said it had received reports of civilian casualties from Pakistani artillery shelling and aerial bombardment as desperate people broke the curfew in search of food and water or to flee hostilities. Many of the trapped civilians were suffering from dehydration and other health problems and their children were particularly weak and vulnerable, it said. The critically injured faced likely death as all medical facilities in the valley had shut down and medicines were unavailable, said the Human Rights Watch. "Civilians continue to suffer at the hands of the Taliban and now their misery is being compounded by the military's disregard for civilians and refusal to allow them to leave the conflict zone," said Adams.