CHICAGO – Democratic presidential candidates took aim at President Donald Trump Thursday, blasting the president and his national security team for recklessly escalating tensions with Iran.

South Bend, Indiana Mayor Pete Buttigieg, a former Navy officer who served in Afghanistan, offered perhaps the sharpest criticism among the crowded field of 2020 candidates about the Trump administration’s increasingly tough talk against Iran.

"This is not a game. This is not a show,” Buttigieg said during a speech before the City Club of Chicago. “We’ve got to make sure that security decisions are not made based on politics but are the right decision"

In Washington, Trump offered a pithy response when asked on Thursday by reporters about whether the administration is on the path to war with Iran.

“I hope not,” Trump told reporters at the White House.

Iran escalation:Asked if U.S. is going to war with Iran, President Donald Trump responds: 'I hope not'

Tensions have been building since the administration this month revoked waivers that allowed Iran to sell oil to some customers despite American sanctions. This week the U.S. ordered its non-emergency government staff to leave Iraq amid fears that the region might be heading toward another conflict.

The Trump administration also has deployed an aircraft carrier ahead of schedule and B-52 bombers to the Persian Gulf to counter what the administration has described as threats from Tehran.

On Wednesday, Trump appeared to try to tamp down concerns about possible military action by taking to Twitter to raise the possibility of diplomatic negotiations with Iran’s leaders.

Still, Buttigieg said after his Chicago speech that it was important for Congress to get “on the record” in formally expressing their opposition to military action against Iran. He said he remains concerned about the situation escalating, even as Trump has toned down the saber rattling.

“The relationship between what the president says and what the president does has always been suspect,” Buttigieg said. “This is something that should be taken extremely seriously, and it’s why I hope and pray there are enough people in Congress to recognize that if there was ever a moment to stop Congress’ abandonment of its own war powers and get on the record on this issue, it is now.”

Rep. Seth Moulton, another Democratic presidential hopeful and former Marine infantry officer who served in the Iraq war, slammed Trump and his national security advisers as “chicken hawks” in an MSNBC interview. Moulton on Wednesday introduced a resolution that would strip the president of his authority to engage in military action without prior Congressional approval.

During his time in Iraq, Moulton and troops under his charge battled with Iranian-backed militias that led a bloody insurgency against U.S. troops in Baghdad and huge swaths of southern Iraq more than a decade ago.

“I fought Iranians in Najaf,” Moulton said referring to the southern Iraqi city. “We won. I’d fight them again if necessary. But this is not necessary. This is chicken hawks trying to drag us into a war with Iran just like they did 15 years ago in Iraq. This is why we need to make national security front and center at the Democratic debates.”

Former Vice President Joe Biden, the frontrunner in the crowded Democratic field, earlier this week suggested that Trump’s original mistake was abandoning a nuclear agreement brokered between the U.S. and allies during the Obama administration.

"The way to prevent Iran from being a nuclear power is to stay in the agreement," Biden told reporters during a campaign stop in Concord, N.H.

Buttigieg saying he found it particularly perplexing that Trump has relied on White House National Security Adviser John Bolton, who helped the George W. Bush administration build its case for 2003 invasion of Iraq.

Bolton earlier this month in announcing the deployment of the U.S. aircraft carrier and B-52 bombers to the region said the Trump administration is “not seeking war with the Iranian regime, but we are fully prepared to respond to any attack.”

“I would also say personnel is policy, and a lot of this energy for conflict is coming from the national security adviser,” Buttigieg said. “I remain mystified that anyone that had that big of a hand propelling us into the Iraq war is allowed anywhere near the situation room.”

Maryland Rep. John Delaney, another Democratic presidential contender, made similar criticism.

“Many of the same individuals that pushed America towards the destructive and costly ‘regime change’ conflict with Iraq are now beating the drums of ‘regime change’ and conflict with Iran," Delaney said. "This behavior is reckless and irresponsible.

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Contributing: John Fritze, Michael Collins and David Jackson