TEHRAN, Iran — Iran's state television has issued its most drastic warning so far about the new coronavirus, saying the outbreak could kill “millions” in the Islamic Republic if the public keeps traveling and ignoring health guidance.

The warning came in a bulletin broadcast on Tuesday afternoon. Roughly nine out of 10 of the over 18,000 cases of the new virus confirmed across the Middle East come from Iran, where authorities denied for days the risk the outbreak posed.

Iran's supreme leader also on Tuesday issued a religious order prohibiting “unnecessary” travel in the country.