From left, Staff Sgt. Bryan C. Black, 35, of Puyallup, Wash.; Staff Sgt. Jeremiah W. Johnson, 39, of Springboro, Ohio; Sgt. La David Johnson of Miami Gardens, Fla.; and Staff Sgt. Dustin M. Wright, 29, of Lyons, Ga. All four were slain Oct. 4 by militants in Niger. (U.S. Army via AP) (AP)

Hours after they first learned of a deadly ambush on U.S. forces in Niger, senior officials in the White House believed that several American soldiers might be missing, according to a senior official familiar with the operation.

The White House did not officially receive word that three American bodies had been recovered, and that one soldier remained missing, until at least eight hours after the attack had begun on the morning of Oct. 4, Washington time.

President Trump was given updates throughout the day but was not given a full briefing on the situation by his chief of staff, John F. Kelly, until the following morning.

“The initial report was more than one person missing and a number of people wounded,” the official said. “It was very confusing.”

The confusion and delays in receiving and transmitting information between field commanders, through the U.S. Africa Command in Germany, to the Pentagon and then to the White House underscores the chaotic nature of the firefight. More broadly, it illustrates the difficulty of determining facts on faraway battlefields. In this case, the lack of firm information over so long a period was especially striking to those on the receiving end.

“My whole life, I’ve never seen something like that happen,” the senior official said of the scramble to determine how many soldiers were missing or dead. “I was dumbfounded by it.”

Nearly three weeks later, Gen. Joseph F. Dunford Jr., the chairman of the Joint Chiefs of Staff, on Monday described the deadly ­Niger attack as a “very complex situation.”

It remains unclear how long it took before officials at the Pentagon and U.S. Africa Command fully understood what had happened and confirmed that one soldier remained missing. Once that was clear, Pentagon officials that evening ordered the deployment of U.S.-based elite commando units to look for Sgt. La David Johnson, an Army mechanic. Johnson was attached to the ­Niger-based Special Operations unit that had come under attack.

It is unknown whether the commandos participated in the search for Johnson, whose body was eventually recovered and turned over to U.S. forces by Nigerien troops on Oct. 6, two days after the attack.

U.S. officials expressed skepticism that Johnson, alive or dead, was ever in the hands of the attacking enemy force, a local group believed to be affiliated with the Islamic State. “I suspect that he got separated” from the rest of the unit and was killed, the official said. “I strongly doubt he was captured by the enemy.” Administration and Washington-based defense officials who discussed the attack and the administration response spoke on the condition of anonymity because they were not authorized to talk to reporters.

Trump, who made no public comment about the deaths until more than a week after they occurred, said Wednesday that he did not “specifically” authorize the original mission, which officials have described as a routine reconnaissance tour by troops based in Niger to train local forces. The 12-man U.S. unit, accompanying about 30 Nigerien soldiers, traveled two hours by land to the village of Tongo Tongo, in the southwest corner of Niger, on Oct 3. The next morning, they spoke with village elders and began the trip back to their base.

U.S. officials are still probing exactly how the travelers were ambushed, became separated on the battlefield and apparently lost communication with each other. The team did not contact its commanders in Niamey for an hour after the attack began.

Two U.S. military officials said Johnson may have lost contact with his unit because they were ambushed twice in succession by the militants. That detail, first reported by NBC News, may explain the delayed call for assistance. Five Nigerien soldiers were also killed.

Dunford speculated that the troops delayed the request for help because they initially thought they had the situation under control.

U.S. officials, who have said that a U.S. surveillance drone was overhead during the incident, described a scene in which small elements of U.S. and Nigerien troops were firing and maneuvering for cover under the enemy assault. “I personally think the American and Nigerien force was just overwhelmed,” the administration official said. “They met up with a pretty serious, professional force.”

Once the besieged U.S. troops contacted their headquarters, U.S. forces in Niamey requested aid from the much larger French military contingent based there. French Mirage jets took off within 30 minutes and reached the scene of the attack, near the border with Mali, a half-hour later. But they did not fire, officials said, to avoid hitting friendly forces scattered along with the enemy across the combat zone.

French helicopters, traveling farther and much more slowly from a base in the Malian city of Gao, did not arrive until an hour after that. It was unclear whether the battle was still underway when they reached the scene.

Still hours later, Dunford received a call from Marine Gen. Thomas D. Waldhauser, head of the U.S. Africa Command, that sparked the Pentagon to deploy members of the secretive Joint Special Operations Command to the region. With Johnson confirmed missing, military officials feared that he might be alive and could fall into enemy hands, three officials said.

The area where the U.S. unit was operating, on what its orders called a “civil reconnaissance mission,” was relatively new to American forces in Niger, who have conducted numerous similar trips to villages in the southeastern part of the country.

U.S. Special Operations forces have been in Niger to train and assist local troops in counterterrorism operations since at least 2005, and now number between 800 and 1,000. They are part of an initiative begun after the September 2001 al-Qaeda attacks, and expanded by the Obama administration, to train and assist government security forces in areas around the world where militant groups might use local unrest to expand their influence.

The U.S. military, which does not have authority for “direct action” offensive operations in the region, also provides logistics and intelligence assistance to the thousands-strong French force in West Africa. France, the former colonial power, deployed troops to Mali in 2012, when Tuareg tribesmen, who had launched a rebellion against the central government, were themselves attacked by Islamist groups tied to al-Qaeda affiliates in Libya.

That French mission later expanded to a more permanent force, called Operation Barkhane, in the Sahel, the arid sub-Saharan region of Chad, Niger, Burkina Faso, Mali and Mauritania. The French are the only foreign force with authorization to conduct direct actions and to cross borders in the region, which also hosts a U.N. peacekeeping force.

As they have spread in Libya, following the 2011 NATO-backed overthrow of Libyan leader Moammar Gaddafi, both al-
Qaeda and more recently the ­Islamic State have sought adherents in the Sahel. They have found willing followers among poor and isolated populations, often abused by local government and military forces, and riven with ethnic and tribal divisions.

Over the last two years, U.S. and foreign officials have noted the rise of at least three new Mali-based Islamist groups, small in numbers but increasingly active in cross-border operations in the region. Officials believe that one of them, the Islamic State in the Greater Sahara, was responsible for the Oct. 4 ambush.

While it is believed to have no more than 60 pledged fighters, the Sahara group is frequently supplemented by sympathetic ­local villagers and temporary ­alliances with other localized groups. It is headed by Western ­Sahara-born Adnan Abu Walid al-Sahraoui, a veteran of an al-Qaeda affiliate that was part of the 2012 violence in Mali. Although the Sahara group was recognized by the Islamic State in late 2016, officials do not believe it receives much support beyond recognition from the larger Middle East organization.

Using small arms and traveling by motorcycle across the savannah, they have staged attacks against local military forces in the tri-border area of Niger, Burkina Faso and Mali, including the part of southwest Niger where the ill-fated U.S. unit was operating at the time of the attack.

Although U.S. officials say they await the results of their own investigation, local officials in the area of the attack said that the Americans and their Nigerien partners suggested local complicity, the Voice of America reported. "The attackers, the bandits and the terrorists have never lacked for accomplices among the local populations," Tongo-Tongo mayor Almou Hassane told VOA's French-to-Africa service by telephone.

VOA said that the village chief, Mounkaila Alassane, had been arrested by Nigerien authorities since the attack.

The Sahara group fighters usually flee across a neighboring border following attacks, where local forces cannot pursue them. France and the United Nations, along with the African Union, have backed formation by the five Sahel governments of a cross-border counterterrorism force with direct action authority. The United States is still considering whether and how to contribute to financial and other support for the group.

Dan Lamothe contributed to this report.