The chief commander of Iran's Islamic Revolutionary Guards Corps (IRGC) has vowed that Iran will pursue any aggressor, even if it carries out a limited attack, and seek to destroy it.
"Be careful, a limited aggression will not remain limited. We will pursue any aggressor," the head of the IRGC, Major General Hossein Salami, said in remarks broadcast on state TV on September 21. "We are after punishment and we will continue until the full destruction of any aggressor."
His comments come a day after U.S. President Donald Trump authorized a "moderate" bolstering of U.S. forces in Saudi Arabia and the United Arab Emirates (U.A.E.) following the September 14 attack on Saudi oil infrastructure that many in the Trump administration blame on Iran.
Iran has denied involvement in the attack, which was claimed by Yemen's Houthi movement, a group aligned with Iran and currently fighting a Saudi-led alliance in Yemen's civil war.
In announcing on September 20 the planned U.S. military action, Defense Secretary Mark Esper said it was a response to requests from the Saudis and the U.A.E. to help improve their air and missile defenses. He said the troops' mission would be "defensive in nature."
"To prevent a further escalation, Saudi Arabia requested international support to help protect the kingdom's critical infrastructure. The United Arab Emirates has also requested assistance." Esper said.
He stressed it was a first step and that he was not ruling out additional moves in the future, and General Joseph Dunford, chairman of the Joint Chiefs of Staff, said details of the deployments will be determined in the next few days.
Esper added that Washington "does not seek conflict with Iran" but that it would be prepared for any situation.
In July, the United States said it was sending some 500 troops to Saudi Arabia as part of a broader move to increase its force in the Middle East following a spate of attacks on oil tankers in the Gulf of Oman that Washington blamed on Iran or its proxies.
Tensions in the region soared again following the September 14 drone and missile attack on the world's biggest crude oil-processing plant in Saudi Arabia, a strong U.S. ally and fierce regional rival of Iran.
Riyadh and several U.S. administration officials, including Secretary of State Mike Pompeo, have asserted that Tehran was behind the attack.
Iran-backed Shi'ite Houthi rebels in Yemen said they were behind the September 14 attack.
But Washington and Riyadh have blamed Tehran directly. Sunni-majority Saudi Arabia, which is leading a coalition of Arab states fighting against the Houthis, on September 18 put on display drone and missile fragments that it said were used in the attack and said they implicated Tehran.
Iran has denied involvement and warned the United States that any attack would lead to an "all-out war" with Tehran.
U.S. media had reported that the Pentagon was set to present a wide range of military options to Trump on September 20 as the president considers how to respond to the attack on Saudi Arabia's oil industry.
The reports said the military would present Trump with a list of potential air-strike targets inside Iran, among other possible responses.
Officials inside and outside the U.S. administration had said the response could involve military, political, and economic actions, and that military options range from no action to air strikes or moves such as cyberattacks.
Washington could also provide additional military support to help Saudi Arabia defend itself from attacks from the north. Most of Riyadh's defense efforts have focused on threats from Houthi rebels in Yemen in the south of the peninsula.
Earlier on September 20, Washington announced it had imposed another round of sanctions on Iran, including on its central bank and its sovereign wealth fund, following the Saudi attack.
Describing the measures as the highest sanctions ever imposed on a country," Trump signaled he was not inclined to authorize an immediate military action on Iran in response to the drone and missile attack.
Iranian Foreign Minister Mohammad Javad Zarif said the fresh U.S. sanctions were a "sign of U.S. desperation."
"But this is dangerous and unacceptable as an attempt at blocking ... the Iranian people's access to food and medicine," Zarif said, speaking after arriving in New York for the annual U.N. General Assembly next week.
In a related development, an Iranian state body in charge of cyber security denied reports that there had been a "successful" attack on some petrochemical and other companies in Iran.
"Based on our observations ... there has not been a successful cyber-attack on oil facilities and other critical infrastructure," said an official statement carried by IRNA.
NetBlocks, an organization that monitors internet connectivity, earlier reported "intermittent disruptions" to some internet services in Iran starting in the evening on September 20.