Trump says we're 'blowing up the whole country' if Iran doesn't make deal in 48 hours

President Donald Trump said in a post to social media that the U.S. struck "many long sought after targets" in Iran on Sunday.

"Big day in Iran. Many long sought after targets have been taken out and destroyed by our GREAT MILITARY, the finest and most lethal in the World," Trump wrote.

Earlier on Sunday, Trump reportedly told the Financial Times that the U.S. has about "3,000 targets left -- we've bombed 13,000 targets."

Trump also suggested to the FT that he is considering a ground operation in Iran, possibly aimed at Iran's Kharg Island oil export terminal in the northern Persian Gulf. Trump said U.S. forces could "very easily" take the island.

"Maybe we take Kharg Island, maybe we don't. We have a lot of options," Trump told the FT, noting that this would "mean we had to be there for a while."

"To be honest with you, my favourite thing is to take the oil in Iran but some stupid people back in the U.S. say: 'Why are you doing that?' But they're stupid people," Trump told the FT.

The administration is reportedly considering a ground operation against Iran in the Persian Gulf to safeguard the strategic Strait of Hormuz, where commercial shipping has been subject to Iranian harassment and tolls since the U.S. and Israel launched the conflict on Feb. 28.

Trump told reporters on Air Force One on Sunday that Iran had given permission for 10 oil tankers to pass through the Strait, and that another 20 more would do so soon.

Speaking to the FT, Trump claimed that Iran's Parliament Speaker Mohammad Bagher Ghalibaf was "the one who authorized the ships" to pass through safely.

Trump also again speculated about the status of Iran's newly-appointed Supreme Leader Mojtaba Khamenei, who succeeded his father Ayatollah Ali Khamenei after the latter was killed by U.S.-Israeli airstrikes on Tehran on Feb. 28.

"The son is either dead or in extremely bad shape," Trump said. "We've not heard from him at all. He's gone."

Mojtaba Khamanei's absence from the public eye has fueled speculation he was badly injured in the American-Israeli attacks, though Tehran has insisted he is alive and safe.

-ABC News' Meg Mistry and Emily Chang

The Lebanese Ministry of Public Health said in an update on Sunday that 1,238 people have been killed since the start of the war in Lebanon, with 3,543 people injured.

The health ministry said 49 people were killed on Sunday, with 116 injured.

A United Nations peacekeeper was killed over the weekend "when a projectile exploded in a UNIFIL position" in Southern Lebanon, according to the organization. Another peacekeeper was critically injured.

UNIFIL, the U.N. Interim Force in Lebanon, said it does not know where the projectile originated from, and an investigation is ongoing.

"Too many lives have been lost on both sides of the Blue Line in this conflict. There is no military solution. The violence must end," UNIFIL said.

-ABC News' Victoria Beaulé

More than a month into the war with Iran, President Donald Trump told reporters on Air Force One Sunday that negotiations with the country are still ongoing, “directly and indirectly,” and that he could “see a deal” with the country coming through “soon.”

"I do see a deal in Iran, yeah. Could be soon," he said.

However, he also acknowledged that “it’s possible we won’t” come to a deal and added, “you never know with Iran.”

Asked if he is still considering boots on the ground and if he would consider doing so without Congressional approval, Trump did not reply yes or no, instead insisting that he has “lots of alternatives.”

“I just have lots of alternatives. We have tremendous numbers of ships over there. We don't need them all because of, you know, the power,” Trump said.

-ABC News' Megan Mistry and Emily Chang