Also Thursday, Egypt acknowledged for the first time that it is holding the brother of al Qaeda's No. 2 man.
In Yemen, local officials were trying to negotiate the surrender of the remaining militants who have been surrounded by security forces equipped with tanks and helicopters, the officials said, speaking on customary condition of anonymity.
The officials said the senior al Qaeda agents Abdul Raouf Naseeb and Sayed Imam el-Sharif were among more than a dozen militants captured Tuesday and Wednesday in an operation in the mountains of Abyan province, 292 miles south of the capital San'a.
Earlier Thursday, the officials had named only Naseeb, who was sought by Yemeni police and U.S. officials and is believed to have survived the November 2002 attack by a CIA-operated drone that killed al Qaeda's chief agent in Yemen, Qaed Salim Sinan al-Harethi, said the officials.
At the time of the drone attack, Yemeni officials did not say that any al Qaeda operatives had survived. On Thursday, security officials said Naseeb was wounded in the attack and then sheltered by tribal sympathizers.
Naseeb allegedly planned the breakout of 10 militants who escaped from an Aden prison in April 2003, the officials added. The militants had been detained in connection with the suicide attack of the U.S. destroyer USS Cole in 2000, which killed 17 American sailors.
El-Sharif is a former leader and chief ideologue of Egypt's Islamic Jihad, whose members killed President Anwar Sadat in 1981. He moved to Yemen in 1996, but is still wanted in Egypt in connection with Sadat's assassination and cases of alleged terrorism as recent as 1999.
El-Sharif's colleague in the Jihad leadership, Ayman al-Zawahri, joined forces with Osama bin Laden's militant group and is now the No. 2 figure in al Qaeda. He's also No. 2 on the FBI list of Most Wanted Terrorists, with a $25 million reward offered for information leading to his capture.
Ayman al-Zawahri's brother Mohammed had been believed in Egyptian police custody for at least three years, but the government never acknowledged it until Thursday.
Interior Minister Habib el-Adly said Mohammed al-Zawahri would stand trial soon but did not say when. He was sentenced in absentia in 1999 for his role in attacks by the militant group Islamic Jihad.
Yemeni security forces surrounded the militants in the mountains late Wednesday. On Thursday, officials told reporters that the area had been cordoned off and the security forces were giving the militants a chance to surrender through the mediation of local figures.
The crackdown came amid reports of planned attacks in Yemen. Security has been noticeably tightened in the capital, San'a, around embassies, foreign companies and government institutions.
Officials say the security forces are searching for Yemeni and Arab fighters, mainly Egyptians and Saudis, who took refuge in Yemen after fighting in Afghanistan alongside bin Laden in the 1980s.
Many Arabs, now referred to as Arab Afghans, went to Afghanistan in the 1980s to fight Soviet troops who were propping up Kabul's government against the onslaughts of Afghan Muslim guerrillas.
Yemen has allied itself with the U.S. war on terrorism, allowing U.S. forces to enter the country and train its military. The country, which long has tolerated Muslim extremists, is the ancestral homeland of bin Laden, whose al Qaeda terror network is blamed for the Sept. 11, 2001, attacks on the United States.
It wasn't immediately clear why the Egyptian government acknowledged holding Mohammed al-Zawahri, although Arab newspaper reports had recently suggested that he was dead in police custody and that American intelligence officials wanted a sample of his DNA.
Those reports came amid speculation that U.S. authorities had captured or killed bin Laden and Ayman al-Zawahri. U.S. military officials have denied capturing bin Laden and have said nothing about netting his deputy.
Montasser el-Zayat, a prominent Egyptian attorney who defended Mohammed al-Zawahri in his 1999 trial, said his former client is not known to have any ties to al Qaeda, though he had been an Islamic Jihad member for years and had spent time in Afghanistan in 1992-94 and returned in 1996.
Mohammed al-Zawahri was last known to be in the United Arab Emirates in 2001, el-Zayat said. El-Zayat said he had been in Afghanistan working with a Saudi-based Islamic relief agency, The International Committee for Islamic Relief.