Iran warned Washington on Wednesday that it would respond "harshly and immediately" to any possible attack on the country following recent attacks on Saudi oil facilities, according to local media.
The statement came after U.S. Secretary State Mike Pompeo's visit to Saudi Arabia to investigate the attacks.
Iran on Monday sent a formal memo to the U.S. through the Swiss embassy in Tehran denying allegations by the Washington that Tehran was behind the drone strikes on Saudi Aramco facilities, according to official news agency IRNA.
"In case of any aggression against Iran, we will respond to it immediately and harshly," the memo said, adding that the country's response would "not be limited only to the source of the threat."
Since 2015, a Saudi-led coalition has been fighting Iran-backed Houthi rebels in Yemen. Thousands of Yemenis have been killed and pushed the country to the brink of famine.
The Houthis, whose mid and long-range ballistic missiles are usually intercepted by the Saudi air defense systems, have in recent months targeted certain strategic locations across Saudi Arabia with armed drones.
U.S. President Donald Trump has accused Iran of directing the attacks as results of the investigation are yet to come.
*Bassel Barakat contributed to this report from AnkaraAnadolu Agency website contains only a portion of the news stories offered to subscribers in the AA News Broadcasting System (HAS), and in summarized form. Please contact us for subscription options.