The Iranian response was sent via Pakistan, IRNA reported.
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."
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.
Kuwait's Defense Ministry spokesperson, Brig. Gen. Saud Abdulaziz Al-Otaibi, said in a statement on Sunday that the country's armed forces detected and "dealt with" several "hostile drones within Kuwaiti airspace."
The incident occurred at dawn on Sunday, Otaibi said in a statement published on X by Kuwait's armed forces.
A bulk carrier ship was struck by an "unknown projectile" in the Persian Gulf off the coast of Doha, Qatar, according to U.K. Marine Trade Operations, a maritime monitoring organization.
"The Master of a Bulk Carrier reports being hit by an unknown projectile," UKMTO said in a warning posted early on Sunday. "There was a small fire that has been extinguished, there are no casualties."
The ship, which was not identified by UKMTO, was about 23 nautical miles northeast of Doha when it was struck, the organization said.
