Tacloban, Philippines (CNN) -- A day after Super Typhoon Haiyan roared through the Philippines, officials predicted that the death toll could reach 1,200 -- or more.
"We estimate 1,000 people were killed in Tacloban and 200 in Samar province," Gwendolyn Pang, secretary general of the Philippine Red Cross, said of two coastal areas where Haiyan hit first as it began its march Friday across the archipelago.
No one is saying that number won't rise.
A provincial police chief reportedly said that local government estimates point to as many as 10,000 feared dead alone in Leyte province, which includes Tacloban. According to AFP, Chief Supt. Elmer Soria said that this figure came out of a Saturday night meeting with the governor of Leyte.
National police and the military sent reinforcements Sunday to prevent looting in the hard-hit city of Tacloban. News video showed people breaking into grocery stores and cash machines in the city, where there had been little evidence of authority since midday Friday.
The store break-ins were attributable to a severe lack of food. Relief efforts were hampered by heavy damage to the airport and trees and debris blocking roadways.
In signs of progress, the road to the airport was cleared Sunday and helicopters were making regular flights.
Death count expected to rise
The government had counted 151 dead, 23 injured and five missing as of Sunday morning. More than 477,000 people were driven out of their homes.
Experts predicted that it will take days to get the full scope of the damage wrought by a typhoon described as one of the strongest to make landfall in recorded history.
"Probably the casualty figure will increase as we get more information from remote areas, which have been cut off from communications," said Tomoo Hozumi, UNICEF's Philippines representative.
The casualties from the storm, which affected 4.3 million people in 36 provinces, occurred despite preparations that included the evacuation of more than 800,000 people, he said.
The National Risk Reduction and Management Council said more than 70,000 families were affected, and nearly 350,000 people were displaced -- inside and outside evacuation centers. Thousands of houses were destroyed, it said.
Tacloban hardest hit
Tacloban suffered the greatest devastation, said Lt. Jim Aris Alago, information officer for Navy Central Command. "There are numbers of undetermined casualties found along the roads."
Officials initially found more than 100 bodies scattered on the streets of the coastal city.
"We expect the greatest number of casualties there," Alago said, adding that 100 body bags had been sent to the area. People were wading through waist-high water, and overturned vehicles, downed utility poles and trees were blocking roads and delaying the aid effort.
Mobile services were down, and officials were relying on radios.
Another 100 residents in this city of 220,000 were injured, said Capt. John Andrews, deputy director of the national Civil Aviation Authority.
Storm damage was swift
Roofs and windows were blown off of and out of many of the buildings left standing.
But the speed of the storm -- which was clocked at 41 mph -- meant residents didn't have to hunker down long. Many emerged Saturday from their homes and shelters and trekked through streets littered with debris to supermarkets, looking for water and food. Several bodies were found at a chapel; a woman wept over one.
National police sent 150 officers to Tacloban on Saturday night, and Director Alan Purisima said Sunday he was sending an additional 120 officers to "keep the peace and restore law and order."
The military also sent a battalion of 500 to patrol the city.
Rescue crews were handing out ready-to-eat meals, clothing, blankets, medicine and water, Alago said.
Red Cross struggling to reach scene
The Philippine Red Cross succeeded in getting its assessment team in to Tacloban but had not managed to get its main team of aid workers and equipment to the city, said Philippine National Red Cross Chairman Richard Gordon.
"We really are having access problems," he said.
The city's airport was shut to commercial flights, and it would be three days before a land route was open, so organizers were considering chartering a boat for the 1½-to-2-day trip, he said.
"It really is an awful, awful situation."
Tacloban, on Leyte island, is the largest city in the Eastern Visayas Islands. It was an important logistical base during World War II and served as a temporary capital of the Philippines.
Some hospitals on Leyte were destroyed, the official Philippines News Agency reported, adding that the Department of Health had sought help from the World Health Organization.
U.N. aid gears up
World Food Programme spokeswoman Bettina Luescher saud the U.N. group was gearing up its global resources to send enough food to feed 120,000 people.
"These high-energy biscuits will keep them alive," she said.
In addition, she said, the world body was sending IT teams and telecommunications equipment to help humanitarian groups coordinate their efforts once they reach the area.
She noted that much of the country's infrastructure -- roads, bridges, airports, ports -- may have been destroyed or damaged and that the government could use help with logistics.
Luescher pleaded for financial support from the international community and directed those wishing to donate to wfp.org/typhoon.
"Those are families like you and me, and they just need our help right now," she said.
The destruction across the islands was catastrophic and widespread. For a time, storm clouds covered the entire Philippines, stretching 1,120 miles -- the distance between Florida and Canada -- and tropical storm-force winds covered an area the size of Germany.
A representative of the humanitarian organization CARE in the Philippines said the agency was trying to bring in supplies but did not know where they might be most needed. "We haven't heard anything from the municipalities on the Pacific side," Celso Dulce said.
The storm first struck before dawn on Friday on the country's eastern island of Samar, flooding streets and knocking out power and communications in most of Eastern Visayas region.
Powered by 195-mph winds and gusts up to 235 mph, it then struck near Tacloban and Dulag on the island of Leyte, flooding the coastal communities.
"It is like a tsunami has hit here," CNN's Paula Hancocks said from Tacloban.
Many islands hit
Haiyan continued its march, barreling into five other Philippine islands before its wind strength dropped Saturday to 130 mph and it lost its super typhoon designation.
On Friday, the Red Cross had more than 700,000 people in evacuation centers, but some of those proved no match for the storm, the Red Cross' Gordon said. "People died there as well."
Meteorologists predicted that Haiyan would weaken to a minimal typhoon or a tropical storm before making landfall Monday morning in northern Vietnam between Hanoi and Vinh. Up to 12 inches of rain were forecast for portions of northern Vietnam near the border with China by Monday night.
By late Saturday, Philippine military helicopters were taking surveys of the disaster; it took relief workers from Manila up to 18 hours to reach the worst-hit isles.
Haiyan packed a wallop on Philippine structures that was 3.5 times more forceful than the United States' Hurricane Katrina in 2005, which directly or indirectly killed 1,833 people. At $108 billion, it was the costliest hurricane in U.S. history.
Haiyan may be the strongest tropical cyclone in recorded history, though meteorologists said it will take further analysis to establish whether it is a record.
Most of Cebu province couldn't be contacted by landlines, cell phones or radio, Dennis Chiong, operations officer for the province's disaster risk and emergency management, said Saturday.
One inaccessible town, Daanbantayan, has more than 3,000 residents who "badly need food, water and shelter because most of the houses there are damaged due to the storm," Chiong said.
In the town of Santa Fe in Cebu province, officials could not determine the number of fatalities because roads were washed out and phone services down.
CNN's Paula Hancocks and Andrew Stevens reported from Tacloban, and Faith Karimi and Tom Watkins wrote from Atlanta. CNN's David Simpson, Elwyn Lopez, Joseph Netto, Michael Martinez, Aliza Kassim, Jessica King, Brandon Miller and Yousuf Basil contributed to this report.