Republican and Democratic senators emerged from a classified briefing about the deadly ambush in the African nation of Niger with different opinions about whether the attack that killed four U.S. soldiers could have been averted.

Sen. Ted Cruz, R-Texas, said Thursday that "on the initial assessment there were not significant steps that could have been taken to prevent this assault." But Sen. Richard Blumenthal, D-Conn., pointed to a shortfall in intelligence and overhead reconnaissance support for U.S. forces in Africa as a potential factor in an attack that caught many lawmakers off guard.

"I could not look those families in the eye and say we're doing everything we need to do to provide sufficient intelligence that will enable them to be successful in their missions and avoid the kind of catastrophe that we saw here," Blumenthal said.

Sen. John McCain, the chairman who has demanded Defense Secretary Jim Mattis keep the Armed Services Committee informed, said the briefing conducted by two senior Pentagon officials shed light in a number of areas. But McCain, who had threatened a subpoena to get information, said other key questions remain unanswered as the U.S. military continues to investigate a tragedy that is evolving into a political dispute.

McCain, R-Ariz., said he wanted to know why it took so long to recover the body of American serviceman, Sgt. La David Johnson, who was missing for two days before his body was found by Niger troops and turned over to the U.S. He said Pentagon officials covered the matter but he indicated they didn't know everything yet.

"I had a lot of questions. All of us had questions," he said.

McCain responded testily when asked if the early October mission that led to the deaths of the American troops in Niger was a failure.

"Do you think there's a failure if four Americans are killed?" he said.

Asked if the result was bad luck or bad strategy, McCain answered: "Both."

The briefing was conducted in a secure room in the Capitol by Robert Karem, assistant secretary of defense for international security affairs, and Air Force Maj. Gen. Albert Elton, the Joint Staff's deputy director for special operations and counterterrorism.

The Pentagon, meanwhile, separately confirmed for the first time that a second U.S. military team was involved in the operation that led to the Americans deaths.

Lt. Gen. Kenneth McKenzie, the director of the Joint Staff, said there was a second team that "had something to do with the operation" and was "involved in the same timeline," but he declined to provide any other details.

The Associated Press reported earlier this week that the ambushed joint U.S. and Niger patrol was asked to help a second team of commandos that had been hunting for a senior member of al-Qaida in the Islamic Maghreb.

A senior defense official said the ambushed team was asked to go to a location where the insurgent had last been seen to collect intelligence. The ambushed team was never asked to search for the insurgent, the official said.

The official wasn't authorized to discuss the details publicly and spoke on condition of anonymity.

Marine Corps Gen. Thomas Waldhauser, the top officer at U.S. Africa Command, testified in March that American forces in Africa are constrained by Congress' failure to provide consistent and adequate defense budgets. He said only between 20 and 30 percent of the command's requirements for intelligence, surveillance and reconnaissance are met — the shortcoming Blumenthal referred to.

"This limits situational understanding, support to operations, and fails to offer threat indications and warnings," Waldhauser testified.

Committee members said they're anticipating the U.S. military to be more involved, not less, in Niger and other African countries.

"The more we succeed in the Middle East, the more we're going to see the snakes run to Africa," said Sen. Thom Tillis, R-N.C. "And we've got to be prepared to advise and assist the nations there that are willing to work with us."

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Associated Press writer Lolita Baldor contributed to this report.

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