Iranian Foreign Minister Abbas Araghchi asserted that Tehran is prepared to resume war with the U.S. and said it will stand firm "even if it comes to a doomsday war."

Asked whether diplomacy has failed, Araghchi told NBC's "Meet the Press" Sunday that there is always hope but repeatedly cast doubts on the Trump administration's intentions.

"[T]here is always hope for diplomacy. But we have no reason, to be honest with you, we have no reason to come back to diplomacy and engage with this administration once again, because of their behavior in the past two years," Araghchi said.

"We stand firm in the face of any aggression against us, even if it comes to a doomsday war," he said, adding "at the same time, we are ready for diplomacy."

"Now there is a very reasonable plan on the table. If they reject it for no reason, this is their fault," Araghchi said.

"We are ready for diplomacy. We are ready for war at the same time," he added.

-ABC News' Nicholas Kerr

President Donald Trump said that he expects more talks with Iran to occur this week as he continues to claim the country wants to make a deal to end the war, an agreement that has continued to elude the president.

"I expect more talks with Iran [this week]. They want to make a deal, but it is not the deal that I want to make. It is what we would have maybe agreed to a year ago. They overplayed their hand," Trump told Axios in a piece published Sunday.

Asked if he was considering new strikes against Iran, Trump responded: "I am always thinking about it."

The president also claimed that more than 20 million barrels of oil transited the Strait or Hormuz over the weekend, which he said was the largest since the start of the war.

"Last night, we took a record amount of oil out from the Hormuz Strait — more than we took out before the war,” Trump told reporters on the White House South Lawn earlier Sunday.

-ABC News' Nicholas Kerr

Iran's Islamic Revolutionary Guard Corps Navy on Sunday claimed to have seized a U.S. Remus 600 unmanned underwater vehicle operating in the Strait of Hormuz, according to a statement published by state media.

The Pentagon did not immediately comment on the IRGC's claim.

-ABC News' Guy Davies

Ali Mohammadi, the deputy political commander of the Islamic Revolutionary Guard Corps Navy, said on Saturday that Iranian forces would target American vessels in the Indian Ocean if heavy fighting with the U.S. resumes.

“If another war breaks out, we will undoubtedly attack and hit their vessels and destroyers even in the Indian Ocean,” Mohammadi said, in comments published by the semi-official Fars News Agency.

The Indian Ocean sits beyond the southern entrance to the Strait of Hormuz and the Gulf of Oman, which have been the focus of Iranian and U.S. maritime actions during the ongoing conflict. U.S. vessels have been operating in the Indian Ocean to enforce their blockade of Iranian ports and shipping.

-ABC News’ Somayeh Malekian

President Donald Trump said Saturday morning that he rejected Iran’s seven-day plan to reopen the Strait of Hormuz, though he did not go into specifics as to why he found the proposal unsatisfactory.

"Well, I'm rejecting their deal. They want to make a deal where we open the Strait immediately because they're losing so badly," Trump said. "We're winning tremendously. We have total control of the Hormuz Strait."

"They want to make a deal. I think that's fine, I like making a deal too. But I'm not. That deal would not be acceptable," he added.

"And what they want to do is immediately open the Hormuz Strait. You know why? Because they're dying. You know why they’re dying? Because they have no money coming in. Because they get their money from the Hormuz Strait," the president said.

-ABC News' Emily Chang