The attack was the first targeting of the U.S. military in Yemen since the Pentagon pulled out all 100 American military personnel based there in January 1993. The pullout followed bombings outside the U.S. Embassy and at hotels where some Americans were staying. The military dropped Yemen as a support base for its operation in Somalia.
U.S. intelligence has blamed Osama bin Laden's Al-Qaida organization for some of those bombings. The State Department's latest report on global terrorism says several Mideast terrorist organizations have representatives and sympathizers in Yemen.
A group calling itself "The Army of Mohammed" or "Army of Aden-Abyan" claimed responsibility for Thursday's attack in two telephone calls and a fax to a Muslim activist in London. Syrian-born Sheik Omar Bakri Muhammad told CBS News Correspondent Tom Rivers that the caller spoke Arabic, quoted from the Koran and promised more attacks on Israeli and American targets.
Aden-Abyan Islamic Army, an offshoot of Islamic Jihad, is an active, militant terrorist organization in Yemen.
In the decade since Marxist South Yemen merged with conservative North Yemen, the country has been plagued by sporadic terrorist kidnappings and bombings.
Last year, about 30 foreigners were kidnapped in several incidents and all were released without harm - a decline from 1998, when more than 60 foreign nationals were abducted.
The U.S. report praised Yemen for expanding security cooperation with other Arab countries last year. It also said the government was better controlling its borders and had set up a new counterterrorist unit.
"Nonetheless, lax and inefficient enforcement of security procedures and the government's inability to exercise authority over remote areas of the country continued to make the country a safe haven for terrorist groups," the State Department said.
Yemeni President Ali Abdullah Saleh, responding Thursday to the attack by a small boat laden with explosives that blew up alongside the USS Cole, said he did not think it was a terrorist attack, disagreeing with the preliminary conclusions of President Clinton and other U.S. officials.
When Clinton met at the White House in April with Saleh, a presidential spokesman said the issue of terrorism did not come up but that U.S. officials have been working with the Yemeni government on ways to combat terrorism in the country.
Most hostages in kidnapping incidents are treated well and released unharmed. But Zein al-Abidine al-Mihdar, leader of Aden-Abyan Islamic Army, was executed in 1999 after being convicted of abducting 16 Western tourists and killing four of them.
At the State Department, officials are preparing travel warnigs that tell Americans worldwide to be cautious in their travels and another that advises against travel to Yemen.
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