Islamabad, Pakistan (CNN) -- The United Nations has established more than a thousand health clinics across Pakistan in the wake of widespread flooding, a U.N. official said.
"Almost 1,200 mobile health clinics are operating across Pakistan," said Maurizio Giuliano with the Office for the Coordination of Humanitarian Affairs. "For many people, this is the only way to receive health care."
Water-borne illnesses from contaminated flood waters have erupted nationwide. At least 1 million Pakistanis have crippling diarrhea or respiratory infections. About 65,000 cases of malaria have been reported.
"More than 2 million people have received health care through this system, especially for diarrhea diseases, acute respiratory infections, skin and eye disease," he said.
"These clinics reach even the remotest areas with teams sometimes walking for six hours and carrying 20 kilograms [44 pounds] of medical supplies on their backs."
The death toll in the country has climbed to 1,738, the Pakistan Disaster Authority said over the weekend. Officials said last week that 17 million have been affected nationwide. The death toll is expected to rise significantly as flood waters continue to recede and more bodies surface.
On Friday, U.S. President Barack Obama issued a presidential order authorizing emergency funds to Pakistan's flood victims, the White House said.
The president said the use of the Emergency Refugee and Migration Assistance Fund was in the United States' interest. Up to $33 million can go toward the country's crisis.
The United Nations warned that a crisis is building in the eastern province of Balochistan, where nearly 2 million people are affected.
There is a "humanitarian tragedy" with immediate threats of water-borne diseases and food shortages, said Mengeshe Kebede, the Office of the U.N. High Commissioner for Refugees' representative to Pakistan.
"We need to scale up our activities in the province, or else I think we are heading for a major humanitarian disaster there," Kebede said.
"I have worked in humanitarian situations globally, and worked in refugee camps in Africa during emergencies, but to be honest I had never seen a situation as devastating as I saw in Balochistan," he said.
CNN's Samson Desta contributed to this story.