French soldiers, seen here in Mali in 2013, have spent years providing training and support to the militaries of Mali, Niger and other vulnerable countries in this corner of Africa where Islamist extremism has become entrenched over the past decade. (Jerome Delay/AP)

The Trump administration has no plans — and anticipates no requests from the Defense Department — to change the mission of U.S. troops in Niger or the rules under which they operate, following the killing of four American service members in a militant ambush there early this month, according to senior administration and defense officials.

At the same time, officials this week expressed consternation over claims, sparked by the deaths, that Congress has been kept in the dark over how many American troops are in West Africa and what they are doing there.

Senior lawmakers, including Sen. Lindsey O. Graham (R-S.C.), a member of the Armed Services Committee, and Senate Minority Leader Charles E. Schumer (D-N.Y.), have said they “did not know” there were up to 1,000 U.S. troops in Niger. Armed Services Chairman John McCain (R-Ariz.) and Sen. Jack Reed, the ranking Democrat on the panel, both demanded more information.

“Let’s get a grip,” responded an administration official familiar with U.S. operations in the region. “This has been known for quite a while.” The U.S. mission, the official noted, began years ago under President Barack Obama, has continued under President Trump, and has been repeatedly expanded and briefed on to Congress by both administrations.

The deaths of the four Americans, along with those of five Ni­ger­ien partner troops in an ambush while they were traveling from an outlying village to their home base, were the first from hostile action that the mission has experienced. The incident has sparked a domestic political firestorm over White House interaction with the family of Sgt. La David Johnson, one of those killed.

Gen. Joseph F. Dunford Jr., chairman of the Joint Chiefs of Staff, spoke about the incident where four U.S. service members were killed in Niger on Oct. 4. (The Washington Post)

While they can defend themselves, U.S. forces based in Niger, and in neighboring Cameroon, have no authorization to conduct “direct action” offensive operations, according to senior officials who spoke on the condition of anonymity to discuss deployments in areas under a terrorism threat. In addition to training and advising local security forces, the United States also supplies logistical and intelligence assistance to a 4,000-member French force whose rules allow targeted offensive action against terrorism suspects.

The Pentagon has said it is still investigating the circumstances of the Oct. 4 attack. Once it determines whether there was a communications, intelligence or other operational failure, officials said, the military will adjust to prevent further incidents.

But there will be no “mission creep,” Gen. Joseph F. Dunford Jr., the chairman of the Joint Chiefs of Staff, said Monday. Administration officials said the policy against terrorist groups in West Africa, including Nigeria-based Boko Haram, and those tied to al-Qaeda and the Islamic State, will continue to focus on assisting local forces, and the French.

Dunford acknowledged that U.S. Africa Command, which has cited a lack of sufficient surveillance and reconnaissance resources, would like to have more. But such requests, he said, are received constantly from commanders all over the world. Most surveillance resources, including drones, are currently devoted to operations in Afghanistan.

The United States operates armed drones out of a base still under construction in Agadez, in central Niger. But those weapons are used in Libya and Somalia, the only places in Africa where direct action by U.S. forces is authorized. Unarmed U.S. surveillance drones are also based at a French airfield in Niamey, the Nigerien capital. Dunford said that a pilotless U.S. aircraft was dispatched to the site of the ambush once commanders were notified, but “did not strike.” He did not say where the drone had come from or whether it was armed.

The Agadez base was first approved in 2014, the year Obama outlined expanding military counterterror operations in a speech at the U.S. Military Academy at West Point. He described “a network of partnerships from South Asia to the Sahel,” allowing training of local forces to address “emerging” terrorism threats, assisting multinational forces and, in particular, facilitating French operations in West Africa.

But U.S. operations in the Sahel — the arid, sub-Saharan swath of Africa that includes Chad, Niger, Burkino Faso, Mali and Mauritania — had begun long before. U.S. Special Operations forces started a train-and-assist program in 2005, and have been authorized by Congress every year since then.

Obama regularly reported troop levels and described their mission in biannual reports to Congress under the War Powers Resolution, including his final report last December indicating a troop total of 575 in Niger and 285 in Cameroon. In June, using nearly identical terminology on the French-support and partner-training missions, Trump reported 645 troops in Niger and “approximately 300” in Cameroon.

The senior administration official said about 200 troops had been added in Niger, some of whom military officials said were working on the Agadez base construction. The administration official said updates on the deployments were delivered in monthly counterterrorism assessments to members of national security committees in both houses of Congress, and by U.S. embassy and military officials on the ground during at least a half-dozen member and staff trips to the region this year.

“You could go to the Africa Command website and find that they have troops there,” Sen. Tom Cotton (R-Ark.) said at the Hudson Institute on Monday. “Second, if you are on the Armed Services Committee, you could attend our hearings and hear testimony that we had troops there.”

Administration officials took issue with statements about mission changes made by Graham on Friday, following a closed-door briefing on West Africa that he and McCain received from Defense Secretary Jim Mattis.

“Here’s what the American people need to know,” Graham told reporters. “The counterterrorism rules under President Obama were overly restrictive” and “you’re going to see more actions in Africa rather than less,” with “more aggressive” rules that will include “status-based targeting” of unidentified but presumed militants.

The senior administration official said there were no plans to authorize such activities beyond where they already are permitted, in Somalia and Libya. In the rest of Africa, the official said, “we remain committed to working with our partners and improving their ability to defeat terrorists.”

The domestic uproar over the deaths in Niger is also likely to draw new attention to a simmering controversy between the administration and France. The French have backed the establishment of a U.N.-funded cross-border counterterrorism force of 5,000 troops, drawn from the five Sahel nations. U.N. Secretary General António Guterres, in an unreleased report to the Security Council, has also recommended some form of U.N. funding.

The administration, which has raised overall questions about the efficacy of U.N. operations and what Trump has said is an unfair burden on the United States to pay for them, is opposed to U.N. funding for the force, especially under the mantle of peacekeeping. The United States is assessed nearly 28 percent of the cost of U.N. peacekeeping missions, one of which already operates in the Sahel.

“The United States is committed to supporting an African-led and -owned G5 force through bilateral security assistance,” a U.S. official said, referring to the Sahel group. “What we don’t support is U.N. authorization or assistance to the force.”

The controversy may come to a head on Monday, when French Foreign Minister Jean-Yves Le Drian plans to chair a Security Council meeting on the subject. France will likely introduce a resolution including funding for the force.

France has said it expects the force to be operational by the end of the year. “Discussions are currently ongoing with the U.S., in good faith and with a common will to reach a mutually agreed solution,” said François Delattre, France’s U.N. ambassador. “We are confident that we will get there soon.”