The death toll from the explosion and fire made it one of the worst U.S. naval accidents in recent history, a Navy spokeswoman said. The number of injuries was not immediately known.
A Navy spokesman said the count of dead crew members was made after a muster of the 1,575-member crew of enlisted men and officers. "It does not reflect a count of actual bodies and is subject to error," a spokesman said.
Officials believed the damage was confined to the No. 2 forward turret and ammunition compartments immediately below it. Though the extent of damage was not immediately available, there was no sign of the accident from an aircraft flying overhead.
The 887-foot-long ship - which was built during World War II but modernized and brought back into service in 1984 - was able to maintain power and was never reported in danger of sinking or becoming immobilized.
Iowa crew members put out the fire in the turret and flooded several compartments holding explosives as a precaution, said Lt. Cmdr. Chris Baumann, another spokesman for the fleet.
Five and one-half hours after the accident, the Iowa rendezvoused with a nearby aircraft carrier, the USS Coral Sea, which carries three doctors and has full medical facilities, Baumann said. Helicopters from the Coral Sea also brought medical equipment to the Iowa and transferred some injured crewmen to the carrier.
Officials at the Norfolk Naval Base in Virginia - home port to the 46-year- old Iowa - set up a counseling center and an information clearinghouse to provide relatives with news and comfort.
The fire was in the second of the two forward turrets, at the loading position of the middle of its three 16-inch guns, said Bruce Nason, a Navy spokesman at the Pentagon. The guns can fire shells weighing more than a ton a distance of 25 miles.
Many of the Iowa's dead were inside the turret when it exploded and burst into flames, Lt. Cmdr. Burnett said. Though the thick steel walls contained the blast within the 1,750-ton gun turret, the walls intensified the force of the explosion and served as a death trap for the sailors inside.
The portion of the turret above deck rotates and can hold 25 crew members during firing. About 50 others are in the lower portions of the turret, which reaches deep into the ship. The huge shells and powder bags for the guns - with barrel bores of 16 inches in diameter - are stored in the turret's lower decks and raised on ammunition elevators to the top, where the powder bags are loaded behind the shells.
Defense Department spokesman Dan Howard said the explosion might have resulted from the blast of a 110-pound gunpowder bag used to fire the guns.
"We assume it was a powder bag," he said in Brussels, Belgium, where he was attending NATO meetings with top Pentagon officials.
Another Pentagon spokesman, Col. Miguel Monteverde, said the explosion could have occurred anywhere inside the turret.
"It is just too soon to tell until an investigation team enters the turret," he said.
The Iowa is to arrive today at Roosevelt Roads, a Navy base in Puerto Rico, said Cmdr. Robert Franzmann of the Atlantic Fleet. Among those on the ship at the time of the accident was Vice Adm. Jerome Johnson, commander of U.S. Second Fleet.
Navy officials were notifying relatives personally of the deaths, Baumann said. Several family members gathered at a gymnasium in Norfolk to await word.
"The major problem is lack of information," said Navy Chaplain Barry Brimhall, who was with the families. "They are very, very frustrated. For those who had husbands or sons in the area of the explosion, they are wondering, 'Was it my husband, my son?' "
"The longer we hear nothing, the better it is," said Sandy Tate of Charleston, W.Va., a relative of crewman Jonathan Tate.
Navy policy requires that families of dead or injured sailors be notified before any list of victims is released to the news media, and not all families had been notified by midevening yesterday, officials said.
The Iowa was participating in naval excerises that involved a total of 29 Navy ships in the Atlantic. In an unrelated incident about 500 miles east of Jacksonville, Fla., yesterday, a Navy frigate and a supply ship collided during the same exercises. One ship was damaged and one minor injury was reported, according to Archie Galloway, a civilian public affairs officer at Norfolk.
Neither the USS Platt, a fleet oiler, nor the frigate USS Tripp was in danger of sinking, Galloway said. The ships were not in the same area as the Iowa.
The death toll aboard the Iowa ranks as the worst loss of life aboard a Navy ship in 20 years.
In 1967, 134 people were killed aboard the aircraft carrier USS Forrestal off the coast of Vietnam when a rocket fired from an aircraft on deck started a huge blaze. The next worst accident was in 1963, when the submarine USS Thresher sank with 129 people aboard, followed by 99 dead in the loss of the submarine USS Scorpion in 1968. In 1969, the destroyer USS Frank E. Evans collided with the Australian aircraft carrier Melbourne in the South China Sea, killing 74 people. An Iraqi missile attack on the USS Stark in May 1987 killed 37 crewmen and wounded 21.
A similar explosion occurred in the center gun turret aboard the heavy cruiser USS Newport News during the Vietnam War in October 1972, killing 20 crewmen and injuring 36.
"It is a great tragedy and a matter of terrible sadness," President Bush said yesterday in Washington. "I will take this opportunity to express my regrets, especially to the families of the kids that were killed."
In addition to its 16-inch guns, the Iowa is equipped with 12 five-inch guns and Tomahawk cruise missiles and Harpoon missiles. It was the model for three other Iowa-class battleships and is among the most heavily armored of U.S. warships.
The Iowa and its sister ships, the New Jersey, the Missouri and the Wisconsin, are the largest battleships ever built except for two Japanese ships of the World War II era, the Yamato and the Musashi.
Retired Navy Capt. David R. Cox, who served aboard the Iowa as a midshipman, said the battleships were pressed back into service because they were menacing weapons that effectively showed off American might.
"They're big and ugly, and survivable, and they look really mean," Cox said. They served the Reagan administration's purpose of convincing would-be adversaries that American military prowess was back on the rise.