U.S. national security adviser John Bolton says Iran should not "mistake U.S. prudence and discretion for weakness."
Speaking alongside Israeli Prime Minister Benjamin Netanyahu in Jerusalem on June 23, Bolton said no one has granted Iran a "hunting license in the Middle East."
The comments come after U.S. President Donald Trump said he called off military strikes on several sites in Iran after a general told him 150 Iranians would be killed, saying the response would not be "proportionate" to the shooting down of an unmanned American surveillance drone by Iran.
Bolton emphasized that Trump had only "stopped the strike from going forward at this time."
The warning followed reports in U.S. news outlets that the United States launched cyberattacks against Iranian military computer systems on June 20, hours after Iran downed a U.S. surveillance drone.
Tehran says the drone violated its airspace, while the U.S. insists the aircraft was shot down over international waters in the Strait of Hormuz.
The Washington Post and AP, citing unnamed U.S. officials, on June 22 reported that the strikes were conducted with the approval of President Trump.
U.S. defense officials refused to confirm the reports.
Trump has said the United States will impose new sanctions on Iran on June 24, without providing details.
But Trump, along with Secretary of State Mike Pompeo, also appeared to ease off recent harsh language toward Tehran.
The president said he was open to quickly reaching a deal with Iran that he said would help the country rebound from a devastating economic crisis largely caused by U.S. financial restrictions.
If Tehran would renounce nuclear weapons, Trump said he would become the country’s “best friend” and would help “make Iran great again."
Pompeo said in a statement on June 22 that “when the Iranian regime decides to forgo violence and meet our diplomacy with diplomacy, it knows how to reach us," he said.
"Until then, our diplomatic isolation and economic pressure campaign against the regime will intensify."
Revolutionary Guards Computer
The Washington Post reported that Trump authorized U.S. Cyber Command to attack Iranian military computers following the June 20 downing of the U.S. drone by Iran's Islamic Revolutionary Guards Corps (IRGC).
Tehran has said the drone was flying over its territory, while the Pentagon says it was over international waters when it was shot down.
AP cited two U.S. officials as saying the cyberattacks specifically targeted an IRGC computer system.
The Post said the attack crippled computers used to control rocket and missile launches.
The Post and AP said the cyberattacks had been developed over the past several weeks as tensions increased between Washington and Tehran.
Speaking on June 23, a senior IRGC commander warned that any conflict in the region may spread uncontrollably.
"If a conflict breaks out in the region, no country would be able to manage its scope and timing," Major General Gholamali Rashid was quoted as saying by the semi-official Fars news agency.
Rashid said the Trump administration "should behave in a responsible way to protect the lives of American forces."
He said Iran is not after a war while adding that the country will defend itself against any kind of "threat and aggression."
The United States blames Iran for attacks on oil tankers in the Persian Gulf and Gulf of Oman. Iran denies any involvement.
The escalating tensions have prompted several international carriers to divert flight routes away from the Gulf of Oman and Strait of Hormuz.
Saudi Arabia's state airline Saudia was the latest carrier to announce late on June 22 it is rerouting flight paths to some Asian destinations in order to avoid Iranian airspace, saying the move is a precautionary measure for aviation safety.
The decision follows the U.S. Federal Aviation Administration's decision to bar U.S.-registered aircraft from operating over parts of the Persian Gulf and the Gulf of Oman, after Iran shot down a U.S. military drone.
United Nations chief Antonio Guterres said on June 23 that it is essential to avoid "any form of escalation" in the Persian Gulf.
"The world cannot afford a major confrontation in the Gulf," Guterres said while adding that "Everybody must keep nerves of steel."