The strikes follow attacks against commercial shipping and service members.
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.
Delegations from the U.S. and Iran entered negotiations in June aimed at a war-ending deal based on a memorandum of understanding signed by both countries.
The U.S. and Iran have nonetheless continued to exchange strikes, with the strategic Strait of Hormuz as the primary flashpoint.
U.S. forces have begun striking Islamic Revolutionary Guard Corps targets in Iran at 12 p.m. on Tuesday, U.S. Central Command said.
"The strikes follow recent attempted attacks by the IRGC against commercial shipping in the Strait of Hormuz and against American service members deployed to the region," CENTCOM said.
On the sidelines of the G20 summit in North Carolina on Tuesday, Treasury Secretary Scott Bessent teased that there would be more sanctions on banks that the Trump administration is alleging facilitate business with Iran as part of their economic pressure campaign on Iran.
When asked, Bessent said that the level of intensity of these sanctions will be the gamechanger in upping pressure on Iran's economy.
"It's something at this level of intensity, the Treasury now has five new authorities, and it is across digital assets. It is across aviation. It is across maritime, and we are flexing every day," Bessent said.
"We are speaking to our allies here, who have all come forward, and we have had a great show of support, whether it's from the EU, the ECB, the the UK, the UAE, the Bahrainians. So we have seen great support around the world, and we have zero tolerance," Bessent later added.
Bessent added his plan to "economically asphyxiate this regime" to get them ready to a deal that President Donald Trump will approve of.
Iran's Foreign Ministry spokesperson Esmaeil Baqaei called recent U.S. strikes a "strategic mistake of its own making" and said the U.S. "are addicted to greed and mistaking negotiation for dictation," at a news conference Tuesday.
On Nuclear weapons, he said it will abide by obligations of the treaty and said Iran sees nuclear weapons "as the most destructive weapons of mass destruction -- are not only contrary to our religious teachings, but also anti-civilization and anti-humanity."
On President Donald Trump's claims that the U.S. incursions aim is to eliminate Iran's nuclear weapon development Baqaei said: "From the beginning, the excuse they raised was an 'imminent threat,' then the danger of Iran's nuclear bomb, something they continue to repeat."
"This is a pattern where the United States fabricates a lie each time to justify its crime. The fact that we prepare ourselves and consider the necessary measures for our defense within the territory of the Islamic Republic of Iran is none of anyone's business," he said.
He went on to insist that Iran has no nuclear weapons development at Pickaxe Mountain.
The ceasefire agreement concluded between Iran and the U.S. in June has proven unstable and too fragile, Russian President Vladimir Putin said at a meeting with Iranian President Masoud Pezeshkian at the Shanghai Cooperation Organization summit in Kyrgyzstan on Tuesday.
"We welcomed the signing of the Iranian-American ceasefire memorandum in June of this year, but unfortunately, the ceasefire proved unstable and too fragile," Putin said.
"In this difficult period, we're trying to provide you with the necessary support, we talked with you about this, we're supplying you with goods that you need," Putin said.
Pezeshkian said Tehran remained ready for diplomacy, but only if Washington returned to its obligations under the June agreement.
Responding to Putin, Pezeshkian said, "We appreciate and thank you for your positions at every stage, both during the period when the fighting and acts of aggression were taking place and under normal circumstances, when the United States was imposing sanctions on us, both at the United Nations and in international forums."
"If the United States returns to its commitments under the aforementioned memorandum of understanding, the Islamic Republic of Iran will immediately reciprocate," Pezeshkian said.
