Trump demands 'unconditional surrender' from Iran. But what happens after?

One week into the United States' war with Iran, questions abound about President Donald Trump's mission and what comes after the fighting ends.

Trump, in a social media post on Friday, demanded "unconditional surrender" from Tehran, after which he said would come the selection of "acceptable" new leaders and a rebuilding of the Middle Eastern nation.

What would constitute unconditional surrender?

"What the president means is that when he, as commander in chief of the U.S. Armed Forces, determines that Iran no longer poses a threat to the United States of America and the goals of Operation Epic Fury has been fully realized, then Iran will essentially be in a place of unconditional surrender," White House press secretary Karoline Leavitt told ABC News Chief White House Correspondent Mary Bruce on Friday.

"Whether they say it themselves or not. Frankly, they don't have a lot of people to say that for them because the United States and the State of Israel have completely wiped out more than 50 leaders of the former terrorist regime, including the supreme leader himself," Leavitt said.

Trump told Axios in a phone interview: "Unconditional surrender could be that [the Iranians] announce it. But it could also be when they can't fight any longer because they don't have anyone or anything to fight with."

Trump and his top officials have outlined four objectives of the military offensive: destroy Iran's ballistic missile capabilities; annihilate their Navy; ensure they can never obtain a nuclear weapon; and prevent the Iranian regime from arming and funding terrorism outside its borders. How long that will take remains an open question, with Trump first estimating four to five weeks but later saying whatever it takes.

But on what comes after for civilians in Iran, particularly who will take control after Ayatollah Ali Khamenei and other senior leaders were killed in U.S. and Israeli strikes, Trump and his team have sent mixed messages.

Trump, in his first statements after Saturday's surprise attacks, said "freedom" for the Iranian people was a goal of the operation. His message for Iranians: "When we are finished, take over your government. It will be yours to take."

But days later, Trump excluded regime change when listing his objectives and Defense Secretary Pete Hegseth rejected the notion this was a "so-called regime-change war" or a "nation-building quagmire."

Trump's since shifted his attention back to future Iranian leadership in various interviews over the past 24 hours.

In a phone call with ABC News Chief Washington Correspondent Jonathan Karl on Thursday, Trump said he needed to be involved in choosing Iran's next leader.

"We don't want them to put anybody in there unless it is approved by us," Trump said. The president previously told ABC News that many of his picks to replace Khamenei had also been "knocked out."

But when pressed by ABC's Karl on what happens after the U.S. military campaign, Trump responded, "Forget about next."

"They are decimated for a 10-year period before they could build it back," Trump added.

Leavitt said on Friday that Trump was "discussing and deliberating" about who might be Iran's next leader, maintaining that the president is committed to being involved in the process.

Currently emerging as a possible replacement to Khamenei is his son, Mojtaba Khamenei. Trump told Axios that would be an "unacceptable" outcome. Trump's also so far poured cold water on the idea of Reza Pahlavi, the exiled crown prince of Iran, being an option to lead the country.

Trump earlier in the week had said the worst-case scenario for his war with Iran would be "we do this and then somebody takes over who's as bad as the previous person. That could happen."

On Friday, in an interview with CNN, Trump elaborated somewhat on his vision, saying Iran does not need to become a democratic state and that he is open to a religious leader ruling the country.

Though Trump emphasized Iran's new leader must "treat the United States and Israel well."

President Trump also told CNN that the process of selecting Iran's leader will "work like in Venezuela," where Delcy Rodriguez is currently serving as acting president following the U.S. capture of NicolasMaduro.

Venezuela's Rodriguez, though, has worked with the U.S. in the aftermath of Maduro's capture. So far, Iranian officials have not said they are talking with the U.S.

"What was their goal? They came here for regime change, perhaps. They came here for rapid victory, so they can control everything. But they have failed," Iranian Foreign Minister AbbasAraghchi said of the U.S. on Thursday in an interview with NBC News.

"There is no request for aceasefire by us.And there is no request for anegotiation with the U.S. fromus.We have never sent any messagesto them," Araghchi added.

ABC News' Emily Chang and Isabella Murray contributed to this report.