Pentagon chief says talks 'still ongoing' to end Afghan war

US Defence Secretary Mark Esper said Wednesday he's not ready to publicly discuss how a U.S. troop withdrawal from Afghanistan would begin under a peace deal with the Taliban.

"Negotiations in some ways are still ongoing," he told reporters traveling with him to Europe.

"I don't want to say anything that gets in front of that or upsets that process," he said.

Esper said he planned to meet for dinner Thursday in Stuttgart with NATO Secretary General Jens Stoltenberg to discuss Afghanistan and give him "a sense of where I think things are" in the push to close a peace deal.

Citing "sensitive negotiations," Esper in the inflight interview declined to talk about specifics, such as the timing of an initial American troop pullout or, more broadly, his level of confidence that the Taliban would live up to their end of any peace agreement.

"The conflict continues on," he said. "They are conducting attacks. The Afghans are conducting attacks. We're supporting Afghan attacks. That's why we think the best way forward if we can get the right deal is a political agreement that leads to a viable outcome."