A risky predawn raid by U.S. Special Operations forces that resulted in the death of the Islamic State’s leader on Thursday was set in motion months ago with a tip that the top terrorist was hiding out on the top floor of a house in northwest Syria.

In brief remarks at the White House, President Biden said the decision to send about two dozen helicopter-borne commandos to capture or kill the leader, Abu Ibrahim al-Hashimi al-Qurayshi, was made to minimize the risk of civilian harm. Military officials said attacking with a bomb or a missile would have been safer for the troops but could have endangered more than a dozen civilians in the house, including several children.

“We made a choice to pursue a Special Forces raid, at a much greater risk than our — to our own people, rather than targeting him with an airstrike,” Mr. Biden said. “We made this choice to minimize civilian casualties.”

Aides said Mr. Biden had approved the raid on Tuesday morning after months of military planning, including dozens of rehearsals and an exercise involving a tabletop model of the building. On Thursday, he called the operation a warning to all terrorist groups. “This operation is testament to America’s reach and capability to take out terrorist threats no matter where they try to hide anywhere in the world,” he said.

In the end, Mr. Biden said, Mr. al-Qurayshi died when the terrorist exploded a bomb that killed him as well as members of his own family. Rescue workers said women and children were among at least 13 people killed during the assault.

Pentagon officials said that 10 civilians, including eight children, had been safely evacuated, and that commanders would review whether the mission had harmed civilians.

Read more: NY Times