WASHINGTON (AP) — U.S. and Iranian negotiators reached a tentative agreement Thursday to extend the ceasefire in the 3-month-old war by 60 days and start a new round of talks on Iran's nuclear program, according to a U.S. official familiar with the matter.

Iran did not immediately confirm any deal. Vice President JD Vance on Thursday evening confirmed there was a tentative agreement, but said it was unclear if President Donald Trump would approve it.

"It's hard to say exactly when or if the president's going to sign," Vance told reporters.

He added: "We're going back and forth on a couple of language points."

WATCH: Vance says U.S. and Iran make progress, but Trump's backing unclear