Gen. Joseph Votel, head of U.S. Central Command, told Congress Thursday that he is responsible for the Jan. 29 U.S. commando raid that cost the life of a Navy SEAL.

"First and foremost I am responsible for this mission," Votel testified before the Senate Armed Services committee. "I am the CENTCOM commander and I am responsible for what's done in my region and what's not done in my region so I accept the responsibility for this."

Votel did not call the mission a success, contrary to the description given by the White House in the days after raid, but the four-star commander said the operation did yield "valuable information."

But he said it came at a steep price. "We lost a lot on this operation. We lost a valued operator, we had people wounded, we caused civilian casualties, lost an expensive aircraft."

The raid, conducted on a moonless night against an Al Qaeda in the Arabian Peninsula safe house in a remote part of Yemen, met immediate stiff resistance, and Navy SEAL Senior Chief Petty Officer William "Ryan" Owens was mortally wounded in a fierce firefight.

A $70 million Marine Corps V-22 Osprey sent to extract the SEALs suffered a hard landing, and could not take off again, so it had to be destroyed on the ground.

The U.S. forces had to call in air support from Marine Corps Cobra helicopters that riddled the compound with gunfire, killing the AQAP fighters, including some women combatants, and an unknown number of civilians, including reportedly an 8-year-old girl who was an American citizen.

Votel said an investigation into the civilian casualties has been completed. He put the number of civilians killed at between four and 12, while local reports said as many as 30 were killed in the raid

Votel also said he accepts responsibility for that loss of life.

"Our intention here was to improve our knowledge against this threat. A threat that poses a direct threat to us here in the homeland," Votel said. "We did gain some valuable information that will be helpful for us."

Notably he did not call the information "vital" or "actionable," adjectives used by Defense Secretary Jim Mattis and a Pentagon spokesman.

There is still an investigation on what caused the V-22 mishap, but Votel said he sees no need for a broader investigation into what went wrong, or his recommendation to order the raid in the first place.

"We did an exhaustive after-action review on this," Votel said. "I presided over that, it was to me."

He said, based on the findings he concluded, there was no need for a further review.

"I think we had a good understanding of exactly what happened on [the] objective and we've been able to pull lessons learned out of that that we will apply in future operations," he said.

Armed Services Committee Chairman Sen. John McCain was harsher in his assessment of the operation, saying while it was not a success, that does not detract from the bravery and sacrifice of the men who carried it out.

"There's a thing called the fog of war," McCain said. "They did the best they could under very difficult circumstances."

But McCain also raised some unanswered questions, such as "when heavy fire was encountered, why the decision was made to continue the mission?"

"I still don't think this committee has an answer to that question," but because his didn't pose the question directly to Votel, he gave no response.

"[The] loss of a $70 million aircraft; you do not capture anyone as was part of the mission, that mission is not a success," McCain said

The Pentagon and Central Command has repeatedly insisted that the mission was aimed at capturing intelligence in the form of computers, cell phones and hard drives, and did not target any individual.

But Votel let McCain's assertion that the plan was for the SEALs to take prisoners for interrogation go unchallenged.

And McCain moved on without demanding an answer, and said whatever the facts, the men were true heroes. "No way does it detract from the heroism and professionalism and sacrifice of the brave men and women who serve under your command," he told Votel.