Iran said in a written message, before the election, that it would not seek to kill then-candidate Donald Trump, according to U.S. officials.
The message from Iran was delivered to the United States on Oct. 14, but was not previously reported, according to The Wall Street Journal on Friday.
It came after a private written warning was sent from the United States to Tehran in September, reflecting the Biden administration's public messaging that threats against Trump were a top national security issue and that it would treat any attempts on the former president's life as an act of war.
Iran has been vowing revenge against Trump for years after he ordered the January 2020 U.S. drone strike that killed Quds Force leader Qassem Soleimani. Iran has also sought to harm other officials from Trump's first administration, including Secretary of State Mike Pompeo, Iran envoy Brian Hook, and national security adviser John Bolton. The three men still have Secret Service protection because of the threats against their lives.
The Biden administration also increased Trump's Secret Service protection in July, after intelligence was received about the alleged Iranian assassination plot.
Iran's reply to the Biden White House message repeated the accusations that Trump committed a crime when he ordered the killing of Soleimani, according to U.S. officials.
The Trump team and U.S. officials did not comment on whether Iran's reply was provided to the president-elect.
Last week, the Justice Department reported the allegations that Iranian agents had plotted to assassinate Trump before the election, adding to ongoing attempts by Iran to target him.
A Pakistani man with ties to Iran was charged in August with plotting to kill Trump.
The newly released message from Iran came after the Oct. 1 Iranian missile attack against Israel, and before Israel's retaliatory strikes on Oct. 26 against Iranian air defense and missile facilities.
The Biden administration added forces in the region before the Israeli strikes against Iran, but the Pentagon says the United States did not play a role in the action.
Meanwhile, Iran has been dismissing claims that it was trying to assassinate Trump, with Foreign Minister Abbas Araghchi referring to the allegations from the United States as a "third-rate comedy."
Officials from the United States said that their message in September to Iran had repeated warnings against harming Trump, but had been sent because of new information. They said they are confident that Iran's leadership saw their message, but wouldn't confirm if the messages had been sent through Switzerland, the country representing U.S. interests in Iran.
Sources close to Iran's leadership said Tehran wants to avoid confrontations with the Trump administration, but some of the president-elect's officials have promised that the administration will return to its maximum pressure approach that caused economic hardships in Iran.