Democratic presidential hopeful Sen. Bernie Sanders (I-Vt.) issued a stark warning Friday about President Trump's decision to order the airstrike that killed a top Iranian general in Iraq.

"Trump promised to end endless wars, but this action puts us on the path to another one," Sanders said during an address to supporters in Anamosa, Iowa.

Sanders echoed other Democratic criticism of Trump's move not to brief more members of Congress ahead of the Thursday strike.

"Trump makes decisions impulsively and without any congressional consultation. Congress needs to reassert its authority over matters of war. Our Founding Fathers had it right," Sanders said.

The progressive senator likened the newly heightened tensions between Washington and Tehran to the 2003 U.S. invasion of Iraq, of which he's been sharply critical.

"All of that suffering, all of that death, all of that huge expenditure of money, for what? It gives me no pleasure to say today we face a similar crossroads of dangers," Sanders said.

"When I voted against the war in Iraq in 2002, I feared that it would result in greater destabilization in the country and in the region," he said. "Today, 17 years later that fear has unfortunately turned out to be a truth."

The remarks come after the Pentagon on Thursday confirmed that a U.S. airstrike killed Gen. Qassem Soleimani, the head of the Iranian Revolutionary Guard Corps-Quds Force.

Iran's Supreme Leader Ayatollah Ali Khamenei said that a "harsh retaliation is waiting" for the U.S. following the Baghdad airstrike.

Former Vice President Joe Biden also reacted to news of the strike on Friday, warning of a direct U.S. conflict with Iran and a resurgence of the terrorist group ISIS.

"The threat to American lives and interests in the region and around the world are enormous," Biden told supporters at a rally in Dubuque, Iowa. "The risk of nuclear proliferation is real and the possibility that ISIS will regenerate in the region has increased. And the prospect of direct conflict with Iran is greater than it has ever been."