President Donald Trump speaks during an "Evangelicals for Trump" campaign rally at El Rey Jesus Evangelical church in Kendall, Fla., on Friday, Jan. 3, 2020. Pedro Portal/Miami Herald/Tribune News Service via Getty Images

President Donald Trump threatened Iran on Twitter, saying the United States has pinpointed 52 Iranian sites - including cultural sites - if the nation retaliates.

The threats come after Trump approved strikes that killed Iranian Maj. Gen. Qassem Soleimani on Thursday, immediately triggering fears of Iranian retaliation.

On Friday, an Iranian commander had threatened counter-strikes against the United States, saying Iran had identified 35 potential targets within striking distance.

Trump tweeted Saturday that the 52 targets the US has identified represent the 52 American citizens held in Iran for more than a year during the hostage crisis.

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President Donald Trump on Saturday issued a volley of new threats against Iran, warning via Twitter that if the nation engages in any counter-strikes on American targets, the United States will target a number of "very high level" sites in Iran, including cultural sites.

Trump tweeted that the US has pinpointed 52 Iranian sites "representing the 52 American hostages taken by Iran many years ago." Iran seized 66 Americans during the hostage crisis in 1979, ultimately holding 52 of them for more than a year.

Trump warned that the targets were "at a very high level & important to Iran & the Iranian culture."

He continued: "Those targets, and Iran itself, WILL BE HIT VERY FAST AND VERY HARD. The USA wants no more threats!"

On Friday, an Iranian commander had threatened counter-strikes against the United States, saying Iran had identified 35 potential targets within striking distance, including American ships in the Strait of Hormuz, Sea of Oman, and the Persian Gulf.

The exchange of threats came after Trump approved strikes that killed Iranian Maj. Gen. Qassem Soleimani on Thursday, immediately triggering fears of Iranian retaliation.

Trump defended Soleimani's assassination in his Saturday tweets, and denouncing Iran's threats of counter-strikes.

"Iran is talking very boldly about targeting certain USA assets as revenge for our ridding the world of their terrorist leader who had just killed an American, & badly wounded many others, not to mention all of the people he had killed over his lifetime, including recently… hundreds of Iranian protesters," Trump tweeted. "He was already attacking our Embassy, and preparing for additional hits in other locations. Iran has been nothing but problems for many years."

The embassy attack Trump referred to was carried out by Iran-backed militias. Though the Trump administration has repeatedly said Iran was preparing "imminent" attacks, it has not provided details on the threats.

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