The Iranian response was sent via Pakistan on Sunday, state media said.
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."
U.S. Central Command said in a post to X on Sunday that the number of commercial vessels "redirected" by the U.S. blockade against Iran is now 61 -- three more than the previous update given on Saturday.
CENTCOM said that more than 20 warships are enforcing the blockade. Four commercial vessels have so far been disabled by U.S. forces, CENTCOM said.
-ABC News' Cindy Smith and Ben Siu
Iranian Supreme Leader Mojtaba Khamenei met the head of Iran's armed forces and briefed the military chief on "new guiding measures to pursue military operations and firmly confront adversaries," according to a report by Iran's semi-official news agency Fars on Sunday.
The report did not state when the meeting occurred. Khamenei has not been seen in public since he was appointed supreme leader in March, succeeding his father -- Ali Khamenei -- who was killed in the opening hours of the U.S.-Israeli war with Iran.
Fars said that Ali Abdollahi -- who commands the Khatam al-Anbiya Central Headquarters -- briefed Khamenei on the readiness of Iran's armed forces.
Abdollahi told Khamenei that Iranian forces are "highly prepared in terms of combat morale, defense and offensive readiness" and would deal with any aggression "swiftly, intensely and powerfully," Fars reported.
-ABC News' Claire Bower
Iranian state media reported on Sunday that Tehran had sent its response to the U.S.-proposed text outlining a possible end to the ongoing war.
IRNA said the response was sent via Pakistani mediators.
-ABC News' Rashid Haddou-Riffi
The United Arab Emirates' Defense Ministry said that its air defenses intercepted two drones "coming from Iran" on Sunday.
"Since the start of Iran's blatant attacks, UAE air defenses have intercepted 551 ballistic missiles and 29 cruise missiles," the ministry said in a statement posted to X.
