The attack on the Cole left 17 sailors dead
Pakistani officials say they have arrested six suspected members of Osama Bin Laden's al-Qaeda network - including the suspected planner of the attack on the USS Cole.
US President George W Bush hailed the arrest of the suspect, Walid Mohammad bin Attash, who he called "a killer, one of the top al-Qaeda operatives.
"He is one less person that people who love freedom have to worry about," Mr Bush said in Washington.
The warship USS Cole was rammed by suicide bombers in a dinghy full of explosives in 2000, killing 17 sailors and wounding 37.
This is a big catch - I think he is very important
Brigadier Javed Iqbal Cheema
US security officials described Mr Attash, who is also known as Khalid, as one of the top 10 al-Qaeda suspects still at large.
Pakistani officials also consider him a major figure.
"This is a big catch. I think he is very important," Brigadier Javed Iqbal Cheema, head of Pakistan's counterterrorism unit, said.
The arrest of the alleged plotter is being described as the biggest success in the anti-al-Qaeda operation in Pakistan since the authorities caught one of Osama Bin Laden's close associates, Khalid Sheikh Mohammed, in March.
Mr Attash is Yemeni. The other five suspects are Pakistanis. They were arrested in Karachi, Pakistan's largest city.
Pakistan's Interior Ministry said the men were arrested on Tuesday, but no announcement was made until later in hopes of catching further suspects.
A nephew of Sheikh Mohammed is among the suspects
It said the six suspects were planning to carry out a series of terrorist attacks in Karachi and other parts of the country. It did not give details of the attacks.
The operation began when police stopped a pickup truck transporting explosives hidden among sacks of potatoes, the Associated Press news agency reported, citing anonymous police sources.
They arrested three Pakistani men, who led them to a fourth suspect who was also detained.
That suspect led them to Mr Attash, who is also suspected of involvement in the 11 September 2001 attacks on the United States.
US officials say he met with two of the hijackers about two years before the attack.
He is also believed to have been a bodyguard of Osama Bin Laden's.
A nephew of Khalid Sheikh Mohammed, the senior al-Qaeda member seized in March, was reportedly among those arrested in Karachi. His name has not been released.
The ministry said it had recovered 150 kilograms of explosives and weapons, including pistols and rifles.