KABUL — A senior commander connected to the Afghan Taliban and involved with the attack against the U.S. Central Intelligence Agency that left eight people dead said Saturday the bombing was retaliation for U.S. drone strikes in the Afghan-Pakistan border region.

“We attacked this base because the team there was organizing drone strikes in Loya Paktia and surrounding area,” the commander said, referring to the area around Khost, the city where the U.S. facility was attacked on Dec. 30. The commander, a prominent member of the Afghan insurgency, spoke on the condition of anonymity.

The suicide attack, which dealt the biggest loss to the agency in more than 25 years, killed a woman who was the station chief along with six other CIA officers and one private-security contractor.

“We attacked on that particular day because we knew the woman who was leading the team” was there, the commander said.

The claims couldn’t be independently verified by Sunday and an effort to contact the CIA over the weekend for comment wasn’t successful.

Both the Afghan and Pakistani Taliban have claimed responsibility for the attacks. In the past, the Pakistani Taliban have claimed responsibility for attacks and Western officials have rejected those claims.

Some drone strikes had been coordinated from Forward Operating Base Chapman, Western officials said. The strikes were to target senior leaders of al Qaeda, the Pakistani Taliban and an Afghan group called the Haqqani Network. The CIA operatives located at Chapman, near the Pakistani border, were involved in cultivating informants to target insurgent leaders using ground raids and drone strikes.

A number of leaders of these three groups have been killed by the strikes, which mostly occur on the Pakistani side of the border. Al Qaeda and the leadership of the Haqqani Network are believed to have bases in this area. The strikes have caused anger in the tribal border areas, stemming from claims that civilians also have been killed.

U.S. officials maintain the strikes are necessary to target insurgent leaders who use the border area as a sanctuary.

The attack that killed the seven CIA officers appears to stem from a strategy of calculated risk in running the spy agency’s informant network, posing a sharp challenge as operations ramp up for the Obama troop surge.

U.S. intelligence and military officials said Friday that the attacker had been recruited as a possible informant and brought onto Chapman, passing through at least one checkpoint. He detonated his charge shortly before being searched, blowing himself up.

It was a “high-level asset meeting gone bad,” said one former intelligence official familiar with the incident.

In providing additional details of the suicide bombing, the agency’s worst loss of life since 1983, former and current U.S. intelligence officials painted a clearer picture of how the agency has battled Taliban and allied militants.

In particular, Chapman appears to have taken a less strict line on security than at other U.S. military bases. Only modest searches are performed there, some U.S. officials say, in the hopes of establishing trust with those who may furnish information. Through its efforts in the region, the CIA has been able to create a large network of informants about the activities of al Qaeda and other militants.

“The CIA team there was very professional, and they knew there was a risk to their security protocols,” an official said. “But they felt the need to gather viable, time-sensitive intelligence was so pressing that it justified the trade-off.”

Some former officers have been critical of the practice. One said allowing informants onto a CIA base was poor spy tradecraft and that officers should meet informants off-base. “In a war zone, they don’t follow standard tradecraft,” the former official said. “If you don’t follow tradecraft rules, this is what happens.”

The CIA is reviewing its security practices on bases. “What happened is being looked at very, very closely,” Marie Harf, a CIA spokeswoman, said.

It appears unlikely the CIA will substantially change its use of informants. One intelligence official said it is stepping up efforts in this area.

U.S. officials are still investigating how the informant, said to be wearing an Afghan National Army uniform, was able to get close enough to so many CIA officers without a more thorough screening. They are also investigating the attack’s source.A U.S. intelligence official, asked about the different security standards for potential informants, said: “Intelligence assets are basically asked to risk their freedom — and often their lives — to collect information on behalf of the United States… It’s a fact of espionage that you frequently have to deal with people you need but don’t or can’t trust.”

Such risks will be amplified as the CIA ramps up its operations in Afghanistan to accompany the military surge President Barack Obama has ordered. The CIA expects to increase its own forces by 20% to 25% in the next 18 months, said one U.S. intelligence official.

The death toll is the largest suffered by the spy agency in three decades and has wiped out decades of experience in counterterrorism, current and former officials say. One former CIA official said the base chief, a mother of three, had counterterrorism experience dating to the agency’s Alec Station, created to monitor Osama bin Laden years before the attacks of Sept. 11, 2001.

The meeting also included a high-level CIA officer who had traveled to the remote base from Kabul. It is unclear whether that person was among those killed.

Chapman houses the CIA detachment and a State Department-run provincial reconstruction team, so it has only a minimal military presence. It was established in the months after the attacks of Sept. 11, 2001, as the U.S. launched its CIA-led offensive against al Qaeda and the Taliban in Afghanistan. The CIA’s presence is an open secret locally, say former intelligence officials.