TACLOBAN, PHILIPPINES (CBS NEWS) - A weakened Typhoon Haiyan slammed into northern Vietnam after devastating the Philippines, where one of the deadliest storms in history is believed to have killed thousands in one city alone.
Some 600,000 people had been evacuated in Vietnam, where at least six deaths were reported. The category 1 storm carried sustained winds of 85 mph when it hit near Ha Long Bay.
In the Philippines, the government and international relief agencies were trying to get emergency aid to the worst-hit areas. On Leyte Island, as many as 10,000 people were feared dead in Tacloban, the provincial capital.
President Barack Obama pledged U.S. aid in the wake of the typhoon, which is known as Yolanda under the Philippine naming system.
"Michelle and I are deeply saddened by the loss of life and extensive damage done by Super Typhoon Yolanda. But I know the incredible resiliency of the Philippine people, and I am confident that the spirit of Bayanihan will see you through this tragedy," Obama said in a statement, using he Filipino word for community spirit.
"The United States is already providing significant humanitarian assistance, and we stand ready to further assist the Government's relief and recovery efforts. Our thoughts and prayers go out to the millions of people affected by this devastating storm," he said.
U.S. Defense Secretary Chuck Hagel directed the Pacific Command to deploy ships and aircraft to support search-and-rescue operations and fly in emergency supplies.
Haiyan hit the eastern seaboard of the Philippines on Friday and quickly barreled across its central islands, packing winds of 147 mph that gusted to 170 mph, and a storm surge of 20 feet.
The typhoon's powerful winds and giant waveswashed away everything in its paths. In Tacloban, corpses hung on trees, lay on sidewalks or remained trapped in flattened buildings.
Adding to the chaos, desperate survivors were looting grocery stores and gas stations in search of food, fuel and water as the government began relief efforts.
"On the way to the airport we saw many bodies along the street," said Philippine-born Australian Mila Ward, 53, who was waiting at the Tacloban airport to catch a military flight back to Manila, about 360 miles to the northwest. "They were covered with just anything - tarpaulin, roofing sheets, cardboard." She said she passed "well over 100" bodies.
On Leyte, regional Police Chief Elmer Soria said the provincial governor had told him there were about 10,000 deaths there, primarily from drowning and collapsed buildings. Most were in Tacloban, a city of about 200,000 that is the biggest on the island.
On Samar, Leo Dacaynos of the provincial disaster office said 300 people were confirmed dead in one town and another 2,000 were missing, with some towns yet to be reached by rescuers. He pleaded for food and water, adding that power was out and there was no cellphone signal, making communication possible only by radio.Reports from other affected islands indicated dozens, perhaps hundreds more deaths.
Video from Eastern Samar province's Guiuan township - the first area where the typhoon made landfall - showed a trail of devastation. Many houses were flattened and roads were strewn with debris and uprooted trees. The ABS-CBN video showed several bodies on the street, covered with blankets.
"Even me, I have no house, I have no clothes. I don't know how I will restart my life, I am so confused," an unidentified woman said, crying. "I don't know what happened to us. We are appealing for help. Whoever has a good heart, I appeal to you - please help Guiuan."
The Philippine National Red Cross said its efforts were hampered by looters, including some who attacked trucks of food and other relief supplies it was shipping to Tacloban from the southern port of Davao.
Tacloban's two largest malls and grocery stores were looted, and police guarded a fuel depot. About 200 police officers were sent into Tacloban to restore law and order.
With other rampant looting reported, President Benigno Aquino III said he was considering declaring a state of emergency or martial law in Tacloban. A state of emergency usually includes curfews, price and food supply controls, military or police checkpoints and increased security patrols.
The massive casualties occurred even though the government had evacuated nearly 800,000 people ahead of the typhoon.
Aquino flew around Leyte by helicopter on Sunday and landed in Tacloban. He said the government's priority was to restore power and communications in isolated areas and deliver relief and medical assistance.
Challenged to respond to a disaster of such magnitude, the Philippine government also accepted help from abroad.
The United Nations said relief operations have begun but that access remained a challenge because some areas are still cut off.
Pope Francis led tens of thousands of people at the Vatican in prayer for the victims. The Philippines has the largest number of Catholics in Asia, and Filipinos are one of Rome's biggest immigrant communities.