Mohammad Bagher Ghalibaf, Iran's chief negotiator and the speaker of the country's parliament, said in a speech posted to Telegram on Sunday that "the era of 'proportionate responses' is over."

The recent Iranian strikes targeting U.S. bases in the Middle East were "only the beginning," Ghalibaf said.

"The rules of the game have changed, and from now on, any transgression against the interests and security of Iran will receive a 'faster, heavier, and more painful' response," Ghalibaf said.

-ABC News' Rashid Haddou

Iran's IRGC navy said in a statement on Saturday that they have targeted three oil tankers which have been sailing through "an unauthorized route" in the Strait of Hormuz, as well as three vessels affiliated with the United States in other areas.

The IRGC navy warned all vessels in the Persian Gulf and near the Strait of Hormuz "not to be deceived" by the U.S. military and refrain from "any suspicious movement" to pass through unauthorized waterways or they would be targeted.

The U.S. has not immediately commented about the claims.

-ABC News' Somayeh Malekian

U.S. forces "permanently disabled" two Iranian oil tankers and "completely destroyed" another after Iran's Revolutionary Guard Corps launched ballistic missiles toward an American aircraft carrier and destroyer, U.S. Central Command said in a statement Saturday morning.

Neither of the U.S. ships were hit and no servicemembers were injured, CENTCOM said, though the fact that an aircraft carrier was apparently targeted is a notable provocation.

"The three Iranian crude oil tankers are part of a multibillion-dollar shadow network that funds the IRGC and its regional proxies. Iran has no means by which to defend them," CENTCOM said in a statement.

"Let the message to the IRGC be clear: If you shoot at two of our ships, we will impose an even higher economic cost —taking out three of yours," said Adm. Brad Cooper, CENTCOM commander. "We will not hesitate to defend American forces, and if necessary, destroy Iran’s limited and exposed oil fleet."

-ABC News' Benjamin Siu and Luis Martinez

President Donald Trump said the war in Iran is "small potatoes" and "not a big thing" for the U.S. and that the U.S. has "essentially" taken over Iran.

Trump brushed off comments from Vice President JD Vance who said he does not consider the Iran conflict to be a war on Thursday.

Trump insisted that it doesn't matter what it's called. Trump also said he can "understand" Vance's assessment and claimed there is "no fighting" at the moment, despite the recent resumption of military strikes on both sides.

"I would say it's a military conflict if you want. Some people could call it. I don't think it matters what you call it," Trump said.