Iran’s Supreme Leader Ayatollah Ali Khamenei has issued a stark warning to the United States, pledging a "harsh response" in the event of American military intervention in the ongoing conflict involving Iran and Israel, Meduza reported Wednesday (June 18) evening.

In a televised address, Khamenei condemned recent comments by U.S. President Donald Trump, stating that “the Iranian people cannot be addressed in the language of threats.”  He emphasized that Iran would firmly resist both an imposed war and an imposed peace.

Khamenei warned that any military action by Washington would result in “irreparable damage” to the United States.

U.S. and Israel heighten pressure on Iran

The escalation follows reports in The New York Times that Iran had prepared missiles for potential strikes against American military bases. Meanwhile, Trump, in a post on Truth Social, demanded Iran’s “unconditional surrender” and claimed that the U.S. has control over Iranian airspace.

Meduza says that according to U.S. media, including The Wall Street Journal, CNN, and CBS News, Trump had approved a strike plan against Iran but ultimately chose to delay the operation, hoping Tehran would abandon its nuclear ambitions.

BBC’s Russian Service reports that when questioned by reporters on Wednesday about potential attacks on Iran’s nuclear facilities, Trump gave a vague response: “Maybe I will, maybe I won’t.”

Analysts suggest that one of the possible targets is Iran’s underground uranium enrichment facility in Fordow, fortified beneath a mountain.

Experts note that only the U.S. possesses bunker-busting bombs heavy enough — exceeding 13 tons — to penetrate such defenses. Israel, according to military observers, lacks such capability.

Exchange of strikes between Iran and Israel

Overnight, Israel launched heavy airstrikes against Iranian positions. Israeli authorities said the aim was to disrupt Tehran’s nuclear program. In response, Iran began retaliatory strikes against Israeli territory.

Amid the escalating hostilities, Iran has experienced a near-total internet blackout for over 12 hours, according to NetBlocks, a global internet observatory that tracks cybersecurity and connectivity.

U.N. Security Council to hold emergency session

The United Nations Security Council is set to convene a second emergency meeting on Friday to address the crisis.  The session, requested by Iran and backed by China, Pakistan, and Russia, follows a similar meeting held last week.

Iran has formally asked for briefings from Rafael Grossi, Director General of the International Atomic Energy Agency (IAEA), and Rosemary DiCarlo, U.N. Under-Secretary-General for Political and Peacebuilding Affairs.