WASHINGTON — An Army special forces combat patrol in the west African nation of Niger did not anticipate resistance and called for air support one hour after being attacked by ISIS-affiliated militants, the Pentagon's top general said Monday.

French fighter jets arrived to support the besieged troops on Oct. 4, but four U.S. soldiers were dead, Marine Gen. Joseph Dunford, the chairman of the Joint Chiefs of Staff, said in a briefing at the Pentagon.

“This area is inherently dangerous,” Dunford said.

The 12-member U.S. patrol did not anticipate being attacked and U.S. rules for troops in the area prohibit missions when attacks are likely, he said.

Dunford identified the attackers as an “ISIS-affiliated” group and characterized the attack as complex, "a pretty tough firefight." He said the attackers used small arms, rocket-propelled grenades and machine guns.

When Sgt. La David Johnson was determined to be missing, “the full weight” of the U.S. government was brought to bear to find him, Dunford said. Johnson's body was recovered on Oct. 6.

Staff Sgt. Bryan C. Black, 35, of Puyallup, Washington; Staff Sgt. Jeremiah W. Johnson, 39, of Springboro, Ohio; and Staff Sgt. Dustin M. Wright, 29, of Lyons, Georgia, were killed along with Johnson in Niger.

Five Nigerien troops were killed in the attack. Niger is a former French colony.

More:More than 1,000 mourn Sgt. La David Johnson and 3 fellow soldiers killed in Niger

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The Pentagon is investigating whether the mission changed after the patrol went out, Dunford said, and whether the troops were adequately equipped, how Johnson got separated from the rest of his unit.

The White House was notified once Johnson was determined to be missing, Dunford said.

Dunford said there was “no utility” in comparing the Niger attack to the Sept. 11, 2012, attack on the U.S. consulate in Benghazi, Libya, in which the U.S. ambassador and three others were killed by Islamist militants. The loss of four soldiers makes the Niger attack "a big deal to me,” he said.

A political controversy

The Niger attack has become more controversial in the last week as President Trump falsely claimed that previous presidents had not made condolence calls to the families of fallen troops. After that claim was debunked, and Trump walked back some of his comments, he called Johnson's widow.

That call, which was overhead by Rep. Frederica Wilson, a Florida Democrat and friend of the family, led to criticisms by Wilson and Johnson's widow, Myeshia, that Trump was disrespectful to Johnson and his family.

"Yes, the president said that he knew what he signed up for, but it hurts anyway. And it made me cry cause I was very angry at the tone of his voice and how he said he couldn’t remember my husband’s name," Myeshia Johnson said on ABC's Good Morning America Monday.

"I heard him stumbling on trying to remember my husband’s name and that’s what hurt me the most, because if my husband is out here fighting for our country and he risked his life for our country why can’t you remember his name," Johnson added. "And that’s what made me upset and cry even more because my husband was an awesome soldier."

Trump has alternately denied making the comments to Myeshia Johnson, criticized Wilson and called her "wacky," and said he did remember Sgt. Johnson's name.

On Thursday, White House chief of staff John Kelly, a retired Marine general, criticized Wilson for politicizing the condolence call, but did not deny that Trump had said the words attributed to him by Wilson. Kelly also criticized a speech Wilson gave in 2015 at the dedication of an FBI building in Miami.

Kelly said Wilson had bragged about securing the money to pay for the building, a claim that was proved to be untrue by a video of the speech. In the speech, Wilson praised then-House Speaker John Boehner for his help, along with Republican Florida Sen. Marco Rubio, among others.

More:The Niger attack, Rep. Wilson and John Kelly: How we got here