U.S. official sees similarities between USS Cole blast and embassy attacks

'A sophisticated attack'

But Clarke said, "They were very large and did extensive damage. This one appears to have been very large and shaped so that the blast went into the ship."

Like the embassy bombings, the attack on the Cole was also well-planned, Clarke said.

"There are similarities in the sophistication of the attack, the pre-planning of the attack," he said. "This is something that began long before the recent violence in the Middle East. This took months to plan, and there are indications of safe houses, and planning, and moving of personnel in. That's a sophisticated attack."

U.S. officials on Friday said they were looking at a number of militant groups in their probe of the attack on the Cole in the harbor at Aden, Yemen, and bin Laden's group, al-Qaeda, or "The Base," topped the list.

The United States accuses bin Laden of organizing a network with followers across the Middle East, including Yemen, and says he masterminded the embassy bombings.

Ali Mohamed, a former U.S. Army sergeant, pleaded guilty Friday to helping plot the embassy bombings, saying he joined bin Laden and others in a holy war to kill Americans anywhere they could be found. He was the first to plead guilty of the 17 key people indicted in the United States for the bombings.

Eight of those named in the indictments are fugitives, including bin Laden.

Clarke said bin Laden typically sends people out into a country years before an attack to lay the groundwork.

"When the message comes to attack, they either do the attack or support an attack team," he said.

U.S. at work against bin Laden

Clarke said the United States continues to work covertly to dismantle bin Laden's network.

"We have quietly gone after that organization, and we're picking it apart limb by limb," Clarke said. "We are not done yet, but we will be."

The Taliban militia that rules Afghanistan has denied that bin Laden was responsible for the attack.

'Failure of intelligence' denied

Clarke defended U.S. preparations for terrorist attacks, saying he had not detected any "failure of intelligence" that could have prevented the attack on the Cole.

"I don't agree we've had a failure of intelligence. There's no basis for saying that," Clarke told CBS.

Yemen, with 2,000 miles of forested coastline and no Coast Guard, appears to have been an ideal location for an attack on a U.S. warship on a refueling stop.

The house, shielded from public view, is where investigators suspect the boat bomb was built

Historically, ships get in and out of Yemen easily, and there is a long tradition of smuggling.

Privately, U.S. officials do not believe that the attack on the Cole was planned in Yemen, but elsewhere in the Arab world

U.S. Navy divers are still working the waters of the area trying to recover clues.

Sources say they are looking for body parts of those who brought a small skip along the port side of the Cole and triggered the explosion.

Investigators have set up crime labs in tents at the boat ramp believed to have been used to launch the suicide attack, about six miles from the Cole's location in the harbor.

At the house where the explosive device was believed to have been put aboard the boat, FBI agents are said to have removed a great deal of evidence.

Yemeni police believe they have also found three other locations used by the bombers. So far, the investigation is still limited to the city of Aden.

One U.S. official said that more than 100 people had now been detained or questioned in connection with the attack.

Last bodies arrive in U.S.

The remains of the last four sailors who were among the 17 killed in the attack arrived at Dover Air Force Base in Delaware late Sunday morning.

The families of two of the victims, Kenneth Clodfelter and Patrick Roy, attended a ceremony on the tarmac as the caskets were removed from the aircraft. The families of the other two sailors were not in attendance.

Adm. Christopher Weaver officiated at the ceremony, as the Navy Band played the song "Eternal Father," also known as "The Navy Hymn."

The bodies of the four sailors were recovered Thursday. Following autopsies, the remains will be turned over to the victims' families.

The remains of eight of the 17 sailors killed in the attack arrived at the Delaware base on Friday. The first bodies were brought home October 14.