Updated 11:30 a.m. ET on Saturday

Secretary of Defense Mark Esper spoke Saturday about a newly reached deal between the U.S. and the Taliban to deescalate the longest-running war in American history.

The "reduction in violence" deal will take place over a seven-day period and ultimately will aim to bring the number of U.S. troops in Afghanistan down to 8,600 from around 12,000 over the following months.

The 8,600 number will still include counterterrorism and training operations.

"It's all conditions-based," Esper told a group of reporters during the Munich Security Conference. "We are going to suspend a significant part of our operations."

The defense secretary said that the seven-day period has not started. A concrete date for when the deal will begin is yet to be determined amid outstanding consultations, including a meeting on Friday involving Esper, Secretary of State Mike Pompeo and Afghan President Ashraf Ghani.

Only after assessing the outcomes of the reduction in violence deal will a more permanent peace deal be discussed.

"If all sides hold up, meet their obligations under that reduction of violence, then we'll start talking about the next part and whether to move forward," Esper said.

The next step would involve the signing of an agreement between the U.S and the Taliban. That would pave the way for intra-Afghan talks to determine the future of Afghanistan and the role the Taliban could play in it.

The U.S. military will monitor the reduction in violence, according to a senior administration official.

This initial agreement was worked out by U.S. Special Representative Zalmay Khalilzad and the Taliban over months of negotiations in Doha, Qatar. The U.S. and Taliban had reached an agreement last summer, but President Trump walked away from that near-deal in September after a U.S. service member was killed in a car bombing in Kabul, Afghanistan.

On Thursday, Trump had indicated that the U.S. was close to working out a deal in a podcast interview with Geraldo Rivera. "I think there's a good chance that we'll have a deal, and we'll see. We're going to know over the next two weeks."

En route to Munich for the security conference on Thursday, Pompeo said U.S. negotiators had made significant progress in recent days.

"[W]e hope we can get to the place where we can get a significant reduction in violence — not only on a piece of paper, but demonstrated in the capability to actually deliver a serious reduction of violence in Afghanistan," Pompeo said. "And if we can get there and we can hold that posture for a while, we may well be able to begin the real serious discussion, which is all the Afghans sitting at a table, finding a true reconciliation path forward — a difficult set of conversations, but one that's long overdue."

The announcement follows an ultimatum by the Taliban earlier this week for a U.S. reply to the group's offer of a weeklong reduction in violence. The Taliban have resisted agreeing to a formal cease-fire until the rest of the deal is in place.

Among the Taliban's demands is that any members of Ghani's government participating in the negotiations be there only as regular citizens, not as officials, The Associated Press reports: "The Taliban do not recognize the Afghan government and have refused to negotiate directly with Ghani, effectively sidelining Kabul from the process." Ghani's future is unclear, as there is still no official winner from last year's presidential election.

The U.S. conflict in Afghanistan began more than 18 years ago, shortly after the Sept. 11, 2001, terrorist attacks. Trump has said it's time for American troops to come home, but a withdrawal of NATO or U.S. forces could result in further instability and violence in the troubled country.

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