(CNN) -- The United States offered extensive assistance beyond drone strikes during a massive anti-terror operation in Yemen, including flying Yemeni commandos to a site where they killed scores of suspected al Qaeda members, a U.S. official said.
U.S. Special Operations troops wore night-vision gear and flew Yemeni forces to a remote, mountainous spot insouthern Yemen, according to a senior U.S. official. The Yemeni helicopters that the U.S. personnel flew were Russian-made, which helped to minimize the U.S. footprint during the operation.
Once there, Yemeni commandos engaged suspected members of al Qaeda in the Arabian Peninsula, the U.S. official said, who added that no Americans took part in actual combat on the ground. This same official identified the American personnel involved as special operations members, who are among the most elite and clandestine in the U.S. military.
The official said the United States aided Yemen's government in other ways as well during the multiday operation, which resulted in the deaths of at least 65 suspected terrorists.
CIA drones are suspected to have targeted al Qaeda fighters, weapons locations and a training camp. The latter is near where about 100 suspected members of the terrorist group met recently, according to video that's appeared on jihadist websites and produced worries that the group could be plotting new attacks.
In the middle of that video, the man known as al Qaeda's crown prince, Nasir al-Wuhayshi, appears brazenly out in the open, greeting followers in Yemen. Al-Wuhayshi is the No. 2 leader of al Qaeda globally and the head of al Qaeda in the Arabian Peninsula, or AQAP, which is considered the most dangerous al Qaeda affiliate.
In a speech to the group, al-Wuhayshi makes it clear that he's going after the United States, saying: "We must eliminate the cross. ... The bearer of the cross is America!"
On Tuesday, Pentagon spokesman Adm. John Kirby declined to detail the U.S. government's involvement in this and other aspects of the latest anti-terror operation, though he did highlight its partnership with Yemen.
"We continue to work with the Yemeni government and the Yemeni armed forces to help them improve their counterterrorism capabilities inside the country," said Kirby. "That work continues, and it will continue."
DNA tests are being conducted to determine if one of the most well-known members of that group -- bomb-maker Ibrahim al-Asiri -- is among the dead, according to Yemeni officials.
A high-level Yemeni government official told CNN that al-Asiri is among those suspected to have been killed in a firefight Sunday between militants and Yemeni forces. DNA test results are not due for several days, the official said.
These comments are the first public acknowledgment that al-Asiri could be among the dead.
Even as that possibility is being examined, U.S. officials said they have no confirmation that al-Asiri is among those killed in an operation that didn't directly target him.
CNN's Greg Botelho contributed to this report.