The Trump administration launched a new bombing attack on Iranian territory Monday night, striking Qeshm Island in the Strait of Hormuz on the eve of the US midterms amid mounting fears of a massive post-election assault.

The Wall Street Journal was first to report the strikes, which a US official characterized as a "defensive measure" in response to Iran's use of surface-to-air missiles against American forces that have been waging a war against Iran since February.

The Journal noted that "in one instance on Monday, Iran's Islamic Revolutionary Guard Corps fired a surface-to-air missile at a US jet fighter, which fired back in self-defense."

The US military did not publicly announce the attack on Qeshm Island, which came hours before American voters were set to head to the polls to decide whether President Donald Trump's party should remain in control of Congress.

The Journal reported that the Trump administration had "purposefully" been keeping its recent campaign of smaller-scale strikes on Iran quiet "so as not to signal any intention of resuming major combat operations."

Kazem Gharibabadi, Iran's deputy foreign minister, said Tuesday that "Iran is prepared for any scenario" and stressed that the country "retains its right to legitimate self-defense until the military aggression has been brought to a complete and permanent end."

Last month, Trump vowed that the US would "not be attacking Iran at any time prior" to the midterms and that the two sides were engaged in "productive discussions."

Vice President JD Vance asserted Monday that he and Trump "both feel really good about the prospect of potentially coming to a negotiated settlement" to end the massively unpopular and destructive war with Iran.

Jamal Abdi, president of the National Iranian American Council, said late Monday that "after eight months of an illegal war, there was finally some hope that a diplomatic agreement might be within reach and this war could end through negotiations rather than spiral into the violent scenarios being threatened after the midterm elections."

"But these deeply alarming revelations suggest we may be heading in precisely the opposite direction," Abdi said of the Qeshm Island strikes and other recent attacks on Iran.

"Every day that Congress fails to intervene is another day this administration is allowed to wage an unauthorized war, conceal its military operations, and gamble with millions of lives," Abdi continued.