"Israel's alarming decision to launch airstrikes on Iran is a reckless escalation that risks igniting regional violence," Senator Jack Reed of Rhode Island said in a statement.

His comment came after Israel carried out a "preemptive" strike against Tehran's nuclear and military sites, in defiance of a call from US President Donald Trump to refrain from attacking Iran.

Reed, the top Democrat on the US Senate Armed Services Committee, warned that the "strikes threaten not only the lives of innocent civilians but the stability of the entire Middle East and the safety of American citizens and forces."

"While tensions between Israel and Iran are real and complex, military aggression of this scale is never the answer," he insisted.

"I urge both nations to show immediate restraint, and I call on President Trump and our international partners to press for diplomatic de-escalation before this crisis spirals further out of control."

Other Democrats also voiced alarm.

"This action ordered by Prime Minister Netanyahu appears to deliberately undermine ongoing American diplomatic negotiations about Iran's nuclear program," Senator Andy Kim of New Jersey said on X.

Senator Chris Murphy of Connecticut agreed.

"This is a disaster of Trump and Netanyahu's own making, and now the region risks spiraling toward a new, deadly conflict," he warned on X.

He also took a political jab at the US president, insisting that Israel's decision to attack "is further evidence of how little respect world powers -- including our own allies -- have for President Trump."

Republican senators responded as well, but with a very different tone.

Tom Cotton of Arkasas insisted on X that "Iran is the world's worst state sponsor of terrorism, has the blood of thousands of Americans on its hands, and is rushing to build not only nuclear weapons, but also missiles that can strike the United States."

"We back Israel to the hilt, all the way."

Ted Cruz of Texas agreed.

"Israel is doing a favor to America right now by taking out Iran's nuclear capacity," he said.