Rubio said the nuclear details would need to be worked out in future talks.
President Donald Trump announced "major combat operations" against Iran on Feb. 28, with massive joint U.S.-Israeli strikes targeting military, government and infrastructure sites.
Following the announcement of a two-week ceasefire, initial U.S.-Iran talks in Pakistan in April failed to reach a peace deal.
Trump later announced the open-ended extension of the ceasefire and the continuation of a U.S. blockade until negotiations are concluded "one way or the other."
A senior Hezbollah leader said the group agreed to a "genuine and comprehensive" ceasefire but will respond to bombings of southern Lebanon by targeting locations deeper than the northern Israeli settlements.
Testifying before the Senate Foreign Affairs Committee, Secretary of State Marco Rubio repeated the claim that Iran desired to build a nuclear weapon and was on the cusp of developing a shield of conventional arms that would allow it to pursue that goal.
"The president chose to act to deny them that point of immunity," Rubio said.
On the odds of an agreement to end the war, Rubio commented on the difficulties of the indirect negotiations, but still asserted a deal was possible.
“There is the prospect before us, which could happen today, it could happen tomorrow, it could happen next week,” he said.
Rubio said Iran had agreed to hold negotiations on its nuclear program.
"That is not a guarantee that ultimately it will lead to a deal that's acceptable to the Senate or acceptable to the American people, but we'll be able to engage them in a process to truly test the proposition of how far they're willing to go,” he said.
Israeli and Hezbollah forces continued their attacks on Tuesday despite President Donald Trump's claim that the warring sides had "stopped shooting each other" after his intervention to prevent escalation on Monday.
Lebanon's state-run news agency, NNA, reported three Israeli strikes in separate areas in southern Lebanon. One person was killed, NNA reported. ABC News has contacted the Israel Defense Forces to request comment.
The Lebanese Armed Forces, meanwhile, said two of its soldiers were wounded by an Israeli drone strike in southern Lebanon.
IDF spokesperson Avichay Adraee also issued new evacuation warnings for residents of the southern Lebanese city of Nabatiyeh, warning of planned "forceful action" against alleged Hezbollah targets in the area.
The IDF said in posts to X on Tuesday morning that air alert sirens sounded due to rocket and drone attacks toward northern Israel.
Hezbollah also claimed a missile attack on an Israeli tank in Hadatha in southern Lebanon in the early hours of Tuesday morning.
-ABC News' Joe Simonetti
The Lebanese Armed Forces said in a post to X on Tuesday that two of its soldiers "sustained moderate injuries as a result of being targeted by a hostile Israeli drone" on a road near the southern Lebanese city of Nabatiyeh.
