Tensions between the U.S. and Iran escalated on Sunday as President Donald Trump weighed options for striking Iran amid the regime’s crackdown on protesters, and Tehran threatened to strike U.S. bases in response.

Trump was briefed in recent days on options for sites to strike in Iran, The New York Times reported, after he issued several threats warning that the U.S. could get involved if the Iranian regime attempted to violently suppress the nationwide demonstrations that have racked the country for several weeks. 

The options include nonmilitary sites in Tehran, the Times wrote, as well as a large-scale aerial strike on military targets, The Wall Street Journal reported. Trump has not yet made a decision whether to proceed and no U.S. military action has been taken in preparation thus far, U.S. officials told the Times and the Journal. 

In response to the reports, Mohammad-Bagher Ghalibaf, the speaker of Iran’s parliament, said on Sunday that the country would attack American military bases in the region if the U.S. follows through, and even raised the possibility of a preemptive strike. Ghalibaf also threatened to attack regional shipping lanes and Israel.

Over the last week, Trump has made repeated threats against the Iranian regime that the U.S. was “locked and loaded” and would “rescue” demonstrators if security forces began killing them. Human rights groups say the death toll has reached over 200 as the protests, sparked by a severe economic crisis in the country, have spread, with protesters explicitly calling for regime change.

The president wrote on Truth Social on Saturday that “Iran is looking at FREEDOM, perhaps like never before” and that the “USA stands ready to help!!!” 

Trump has floated the possibility of regime change in Iran before. During the country’s June war with Israel, when the U.S. struck nuclear sites inside Iran, Trump wrote on social media that the U.S. knows “exactly where the so-called ‘Supreme Leader’ [Ayatollah Ali Khamenei] is hiding. He is an easy target, but is safe there — We are not going to take him out (kill!), at least not for now.” Later, he wrote, “It’s not politically correct to use the term, ‘Regime Change,’ but if the current Iranian Regime is unable to MAKE IRAN GREAT AGAIN, why wouldn’t there be a Regime change??? MIGA!!!”

GOP lawmakers have voiced their support for renewed U.S. strikes on Iran, with Sen. Lindsey Graham (R-SC) sharing a message to Khamenei on Fox News last week: “You need to understand, if you keep killing your people who are demanding a better life, Donald J. Trump is gonna kill you.”