The United States military has dropped a 22,000-pound bomb on ISIS forces in Afghanistan, ABC News confirmed through sources at the Pentagon.

It's the largest bomb the U.S. has ever used in combat.

The "MOAB" -- which stands for Massive Ordnance Air Blast but is also known as “The Mother of All Bombs” -- was dropped from a U.S. aircraft at 7 p.m. local time in the Nangarhar Province of Afghanistan. The Pentagon says a series of caves there is being used by ISIS.

General John Nicholson, Commander of Resolute Support and United States Forces in Afghanistan, ordered the use of the bomb. It's the first time the bomb has been used in combat.

President Trump, who had been critical of former President Obama's management of the war against ISIS, called Thursday's use of the bomb a success.

"We have given them total authorization," Trump said of the military. "This was another very, very successful mission."

READ: So, what exactly is a 'MOAB' bomb?

ABC News posted a military statement to Twitter, in which the military said it "took every precaution to avoid civilian casualties." (Reading this on the WFAA mobile app? Go here.)

Nicholson called the target an "ISIS tunnel complex."

"This is the right munition to reduce these obstacles and maintain the momentum of our offensive against ISIS," the general said in the statement.

Nicholson sought authorization from higher commanders for the use of the bomb, which was moved to Afghanistan some time ago as planning for the mission was underway.

Afghan forces and the American troops advising them have engaged in heavy fighting with ISIS forces in Afghanistan over the past year.

An American special operations soldier was killed last weekend in combat operations against ISIS in Nangarhar province.

This video, courtesy of the Department of Defense, shows a 2003 test of the GBU-43B.