Nine former U.S. ambassadors on Tuesday warned that Afghanistan could collapse in a "total civil war" if President Donald Trump withdraws all U.S. forces before the Kabul government and the Taliban conclude a peace settlement.

"A major troop withdrawal must be contingent on a final peace," the nine wrote on the website of the Atlantic Council, a think tank. "The initial U.S. drawdown should not go so far or so fast that the Taliban believe they can achieve military victory."

The nine, including five former ambassadors to Kabul, a former special envoy to Afghanistan and a former deputy secretary of state, issued their warning a day after U.S. chief negotiator Zalmay Khalilzad announced a draft accord with the Taliban for an initial drawdown of nearly 5,000 U.S. troops.