US Secretary of State Mike Pompeo said there has been a "pretty important breakthrough" in peace talks with the Taliban in recent days.
Defence Secretary Mark Esper earlier said they had "negotiated a proposal" for a week-long reduction in violence. The two sides have long been engaged in negotiations aimed at ending the 18-year war in Afghanistan.
But they have been fraught with challenges. President Donald Trump declared the talks "dead" in September.
On Thursday, Pompeo said the US president had given the go-ahead for further talks. He hailed recent progress, but said the negotiations were complicated and that a peace deal had not yet been reached, the BBC reported.
"We hope we can get to the place where we can get a significant reduction in violence, not only on a piece of paper," he said. "If we can get there and we can hold that posture for a while, we may well be able to begin the serious discussion which is all the Afghans sitting at a table finding a true reconciliation."
His comments came after Esper told reporters about the proposal for a "seven-day reduction in violence".
"We've said all along that the best, if not only, solution in Afghanistan is a political agreement. Progress has been made on this front and we'll have more to report on that soon," he said. "It will be a continual evaluative process as we go forward - if we go forward."
Details about when the partial truce was set to begin were not immediately clear, but a Taliban official told a leading media outlet that the group would begin a "reduction of violence" on Friday.
Trump has made withdrawing US troops from Afghanistan a key foreign policy aim. Some 13,000 US troops remain in Afghanistan after the US intervention to oust the Taliban in 2001.