US President Donald Trump said on Monday evening that "it's getting very close" to achieving objectives in Iran, noting that he doesn't think boots on the ground will be necessary.

In a series of posts on X on Monday evening, Kellie Meyer, White House Correspondent for News Nation, said she just spoke to Trump in a two-minute call.

In his first reaction to the attack on the US Embassy in Riyadh, Trump told Meyer that "you'll find out soon" what his retaliation will be.

When asked on the threshold of US boots on the ground, Trump said, "I wouldn't give you anything on that. I mean I don't think they'll be necessary."

Trump's remarks came a few hours after Secretary of State Marco Rubio said the Trump administration believes that its objectives against Iran "can be achieved without ground forces."

"Right now, our focus is on the destruction of their ballistic missile launchers, their ballistic missile stockpiles and their ballistic missile manufacturing capability, as well as their one-way attack drones and their Navy," Rubio told reporters on Capitol Hill before a classified briefing for congressional leaders on Monday afternoon.

Meanwhile, Amir Saeid Iravani, Iran's permanent representative to the United Nations (UN), called on the UN Security Council to "act firmly, clearly, and without ambiguity" in response to the US and Israeli attacks.

In a statement to the press, Iravani said the United States, in full coordination with Israel, launched "a second deliberate and unprovoked" military attack against Iran, which was "a calculated act of aggression."

Iravani accused the US and Israel of "deliberately targeting civilians and civilian infrastructure," resulting in the death of 165 students in an elementary girls' school in southern Iran's Hormozgan province, saying that "these acts constitute aggression. They constitute war crimes. They constitute crimes against humanity."