MANILA, DEC. 21 -- More than 1,500 Christmas travelers were feared dead today when a passenger ferry collided with an oil tanker, exploded into flames and sank in shark-infested waters south of Manila in what could be the world's worst peacetime shipping disaster, surpassing the death toll of the Titanic.

Survivors told reporters at a hospital here that the ferry was so overcrowded that there could have been 3,000 passengers on board -- twice the number the vessel was licensed to carry.

Only 26 survivors, including two of the oil tanker's 13 crewmen, were plucked from the waters. Most suffered serious burns after flaming oil from the tanker turned the water around the two ships into an inferno. Several people who jumped ship were eaten by sharks, Reuter reported, citing radio interviews with unnamed officials.

Navy and Coast Guard ships, commercial vessels, three U.S. Air Force helicopters, and even the presidential yacht combed the waters for survivors today, but by tonight the search appeared to be futile, with rescuers reporting no signs of life, or even signs of the accident.

At about 10 p.m. Sunday, the Victor, a small oil tanker loaded with about 8,800 barrels of oil, ripped into the Dona Paz, an interisland ferry bound for Manila with 1,493 passengers and crew officially listed -- the maximum number it was authorized to carry, the Coast Guard said.

The collision occurred in a channel between the islands of Mindoro and Marinduque, about 110 miles south of Manila. Both vessels sank in waters with a depth of about 1,740 feet.

Upon impact, the tanker ruptured and its oil burst into flames, which quickly spread to the ferry and surrounding waters, survivors said.

Panic spread with the flames and choking smoke among the passengers who were crammed into the ferry. According to survivors, companionways were impassable because they were packed with passengers, luggage, even goats and other animals. On the ship's deck one-man cots were occupied by up to four people.

Survivors spoke of feeling the jolt as the ships collided, of seeing fire and smoke fill the ferry and of hearing screams of fellow passengers. "I heard many people shouting, 'Momma! Poppa! Where are you?' " Francisco Mingote told The Associated Press.

One survivor, Almario Balanda, said that minutes before the collision he had gone below deck to the ferry's dining hall. It was too crowded, so he returned to the upper deck. He said he felt a tremendous impact, and the night exploded into fire.

"I saw many people, some of them screaming," he said. As the flames quickly engulfed the ship, he jumped overboard. "When I jumped into the water, fire surrounded me, so I dived and swam . . . to get away from the fire," Balanda said.

One survivor, 19-year-old Renato Asistorga, told Reuter of seeing "the floating bodies of children and old people in the water. The rescuers did not pick them up anymore. They were busy saving those still alive."

Authorities would not comment on reports from some survivors that the ferry was packed with more than 3,000 passengers, twice its licensed capacity.

But authorities acknowledged confusion over just how many people were on board, according to Reuter. "We can't really say, we're waiting for more reports," said Coast Guard spokesman Lt. Cmdr. Rene Luspo. Coast Guard Lt. Robert Noblefranca said that some passengers, such as children and those who boarded with no tickets, would not have been listed on the official manifest.

According to the AP, the ferry's owners said they could not be certain of the exact passenger count because the ferry had made a stop at Samar Island after beginning its voyage to Manila from the central Philippine port city of Tacloban, capital of Leyte Province. Lt. Noblefranca, commander of the Coast Guard station at Tacloban, said the ship was packed when it left the port early Sunday morning.

The death toll may exceed that of the worst peacetime disaster in maritime history, the sinking of the British liner Titanic, which struck an iceberg and sank on its maiden voyage on April 14, 1912, claiming the lives of 1,503.

Interisland ferries are the cheapest means of transport throughout the archipelago, and the usually crowded vessels become even more packed during holidays.

In Manila, scores of relatives thronged the offices of the Sulpicio Lines, owner of the ferry, anxiously awaiting news of loved ones.

Capt. Melecio Barranco, captain of the Don Claudio, which was the first ship to arrive on the scene and ferried the 26 survivors to Manila, said the Dona Paz burned until shortly after midnight before sinking. The Victor sank about two hours later, he said.

Barranco said his crew gave up the search Sunday evening after sweeping the waters with searchlights for nearly four hours.

The Philippine Navy searched the site throughout the day today with patrol boats, a plane and a helicopter, assisted by four commercial vessels. But as darkness fell today, nearly 24 hours after the disaster occurred, there were no signs of survivors, authorities said.

Capt. Maryellen Jadick, a U.S. Air Force spokeswoman, told the AP that the three helicopters from Clark Air Base "found absolutely no debris, they saw no survivors. It was as if it never happened."

"We covered about 100 miles of sea area, and except for maybe a piece of driftwood or two, we saw absolutely nothing as far as a shipwreck, oil spill, signs of life or signs of an accident," said Staff Sgt. Cliff Davis, a spotter on one of the Air Force helicopters.