“He's going off on a tweet storm on his own,” Biden said in response to Trump’s tweets on Saturday threatening to target 52 sites in Iran if the nation retaliated for the killing of Qassem Soleimani. “And it's incredibly dangerous and irresponsible.”

Biden took no questions from reporters after his brief remarks.

His comments were the latest in a series of attacks on Trump since the president ordered the killing of Soleimani on Thursday night. Since then, Biden, on a five-day tour through Iowa, has sought to hold up Trump’s actions as evidence that the stakes are higher than ever on the world stage. And as a former vice president and former chair of the Senate Foreign Relations Committee, Biden has repeatedly argued before crowds that he’s the only candidate immediately prepared take the reins.

“This all just reinforces the stakes of this election in my view,” Biden told Iowans Saturday. “With all due respect, I think I’m better prepared than of anybody running for president right now.”

However, during a question and answer session here Saturday, the talk of violence in the Middle East soon turned the spotlight to Biden’s record. Biden was asked about his past vote supporting the war in Iraq and whether, as vice president, he advised Barack Obama not to go forward with the killing of Osama Bin Laden in 2011.

Biden’s response was at odds with his own 2012 retelling, in which he said Obama turned to him and asked, “Joe, what do you think?”

“Mr. President, my suggestion is don’t go,” Biden said.

On Saturday though, Biden told a version of the story that he revised in 2015. According to this account, Biden initially wanted more time to make certain of Bin Laden’s whereabouts. In front of others, he cautioned Obama. Then he later gave Obama his final opinion in private.

"I went up to the Oval Office, I said, ‘Mr. President, follow your instincts, go,’" Biden said Saturday.

The Democrat’s latest criticism of Trump was in response to a series of tweets the president authored Saturday in defense of his order to kill Soleimani.

“He was already attacking our Embassy, and preparing for additional hits in other locations. Iran has been nothing but problems for many years. Let this serve as a WARNING that if Iran strikes any Americans, or American assets, we have … targeted 52 Iranian sites (representing the 52 American hostages taken by Iran many years ago), some at a very high level & important to Iran & the Iranian culture, and those targets, and Iran itself, WILL BE HIT VERY FAST AND VERY HARD. The USA wants no more threats!”

Biden referred to Trump’s remarks on social media as a “tweet storm,” and said it was unclear whether the president was acting with or without the counsel of his advisers.

“This is a guy who seems to be unmoored. You may remember some of you asked me this question a long time ago. I said, ‘the more the walls close in on this guy, the thing I worried most about him doing something irrational, maybe getting us into a war.’”

In front of his biggest crowd of a bus tour Biden began on Thursday, the former vice president reiterated many of the remarks he made earlier to reporters, and won big applause when he said Trump had no authority to take action against Iran without the consent of the American people.

Biden asked if anyone had confidence that Trump knew what the next steps were in the Middle East.

The crowd shot back, “NO!”

