NEW YORK — When President Biden told global leaders this week that he had ended America's era of insurgent war, his assertion appeared to contrast sharply with the prolonged military missions that have locked the United States in low-level conflicts in Africa and the Middle East.

Speaking before the U.N. General Assembly on Tuesday, Biden vowed to launch a new period of “relentless diplomacy” after the war in Afghanistan and turn toward Asia after two decades of counterterrorism campaigns set in motion by the 9/11 attacks.

“I stand here today for the first time in 20 years with the United States not at war,” Biden said. “We’ve turned the page.”

Meanwhile, a force of more than 3,000 American military service members are arrayed on bases across Iraq and Syria, dug in on an extended mission against the Islamic State that exposes them to dangers including drone and rocket attacks.