Retired General Responds to Trump's Criticism of U.S. Strategy to Combat Islamic State

WASHINGTON (TheBlaze/AP) — Appearing on ABC's "This Week" Sunday, Retired Gen. John Allen told host George Stephanopoulos that Republican presidential candidate Donald Trump has "no credibility" to criticize him about the U.S. battle against Islamic State militants.

Last week, while campaigning in Colorado, Trump called Allen a "failed general," saying he hadn't done so well in fighting IS. He also attacked the retired four-star general while holding a rally in front of military aircraft, and slammed a Colorado Springs fire marshal for capping attendance at his event.

Gen. John Allen says Donald Trump "has no credibility": "I don't have to justify myself to him." #ThisWeek https://t.co/tqWcFKgKCX

— This Week (@ThisWeekABC) July 31, 2016

Allen is a former commander of U.S. and NATO forces in Afghanistan and also was the president's former special envoy for the global coalition to counter IS. In that job, he worked to assemble a group of nations to counter Islamic State militants.

Allen said he doesn't think he has to justify himself to Trump, who has never spent time in Afghanistan or Iraq and has never served in the military.