The military’s top officer on Thursday described Confederate leaders as traitors and said he is taking a “hard look” at renaming 10 Army installations that honor them, despite President Trump’s opposition to any changes.

“The Confederacy, the American Civil War was fought, and it was an act of rebellion,” the chairman of the Joint Chiefs of Staff, Gen. Mark A. Milley, told members of the House Armed Services Committee. “It was an act of treason at the time against the Union, against the Stars and Stripes, against the U.S. Constitution, and those officers turned their back on their oath.”

The Army is now about 20 percent black, he said.

“For those young soldiers that go onto a base — a Fort Hood, a Fort Bragg or a fort wherever named after a Confederate general — they can be reminded that that general fought for the institution of slavery that may have enslaved one of their ancestors,” he said.

Last month, Trump rejected calls to rename installations after Defense Secretary Mark T. Esper signaled a willingness to do so, saying his administration “will not even consider” that plan.

Milley stopped short of offering a policy prescription for how to handle the installation names, which has become a flash point at the Pentagon, as the nation grapples with the history of racism in the wake of George Floyd’s death at the hands of police in May.

The installations, all in former Confederate states, were named with input from influential local residents during the Jim Crow era. The Army courted their buy-in because it needed large swaths of land to build bases during the military buildups of World War I and II.

That decision was political, Milley told the committee, and renaming the installations would also be a political move.

Two of the Army’s biggest installations are named after Confederate commanders and avowed white supremacists.

Fort Bragg in North Carolina, the headquarters of the Special Forces, bears the name of Gen. Braxton Bragg, who is often assailed as one of the most bumbling commanders in the Civil War. Fort Benning in Georgia, the home of Army infantry and airborne training, is named after Brig. Gen. Henry Benning, who laid out the protection of slavery as the motivation for secession in a speech in 1861.

The other bases named after Confederate commanders are forts Lee, Pickett and A.P. Hill in Virginia, forts Polk and Beauregard in Louisiana, Fort Hood in Texas, Fort Gordon in Georgia and Fort Rucker in Alabama.

The Pentagon has also considered a blanket ban on the Confederate flag in public places at all military installations.

During the hearing, Milley and Esper also jostled with lawmakers over reports about an alleged Russian program to pay militants bounties to attack U.S. and NATO forces in Afghanistan that may have resulted in American deaths. Esper and Milley said defense intelligence agencies could not corroborate the information.

At one point, Esper said he had not received an intelligence report that specifically used the word “bounty” but later said he received reports that broadly mentioned payments.

During the hearing, Esper also defended the use of National Guardsmen to aid police as protests over Floyd’s death spread across the country. National Guard troops were alongside law enforcement as authorities removed demonstrators from Lafayette Square near the White House on June 1 so that Trump could visit a nearby church.

The Guardsmen “did not advance on the crowd,” fire rubber bullets or use chemical agents such as tear gas. Their role was static support, Esper said.

But lawmakers criticized what occurred hours later as a much more kinetic action. Helicopters from the D.C. National Guard — whose chain of command goes directly to the Pentagon — roared over protesters as low as 45 feet from the ground, an analysis by The Washington Post found.

Esper launched an investigation into the use of the helicopters. The report is under review with the Pentagon’s inspector general and could go to the committee next week, Esper said.