The Iranian foreign minister warned Thursday that the United States would bear "legal responsibility" for any Israeli attack on Iranian nuclear facilities, escalating tensions even as the two nations prepare for nuclear negotiations in Rome.
Foreign Minister Abbas Araghchi issued the warning in a letter to the United Nations after CNN reported Tuesday that Israel was making preparations to strike Iranian nuclear sites.
The threat came ahead of a fifth round of Omani-mediated talks scheduled for Friday between Iranian and American officials.
"We believe that in the event of any attack on the nuclear facilities of the Islamic Republic of Iran by the Zionist regime, the U.S. government will also be involved and bear legal responsibility," Araghchi wrote in the letter published Thursday.
The foreign minister added that "Iran strongly warns against any adventurism by the Zionist regime and will respond decisively to any threat or unlawful act by this regime."
The nuclear discussions, which began April 12, represent the highest-level diplomatic contact between Iran and the United States since 2018, when President Donald Trump withdrew from the multinational nuclear agreement with Iran during his first presidency.
Israel has repeatedly threatened military action against Iranian nuclear facilities since the current round of talks began. On Thursday, Ali Mohammad Naini, spokesman for Iran's Islamic Revolutionary Guard Corps, warned of retaliation should Israel follow through on such threats.
"If the delusional Zionist regime commits a foolish act and launches an attack, it will definitely receive a devastating and decisive response in its small and vulnerable geography," Naini said, according to the ISNA news agency.
The escalating rhetoric coincided with demonstrations near Iran's Fordow nuclear enrichment facility south of Tehran, where protesters voiced support for the country's nuclear program.
Demonstrators waved Iranian flags and chanted slogans including "Nuclear energy is our inalienable right" and "No compromise, no surrender, only confrontation with America."
Iran and Israel, which do not maintain diplomatic relations, have engaged in what analysts describe as a shadow war for years. Iran typically refers to Israel as the "Zionist regime" and does not recognize its legitimacy.
The adversaries exchanged direct military strikes for the first time last year amid heightened regional tensions stemming from the conflict in Gaza.