Illinois Rep. Adam Kinzinger (R) took issue Wednesday with President Trump's plan to withdraw 2,000 U.S. troops from Syria and the president's declaration of victory over ISIS in the country. 

"We have defeated ISIS in Syria, my only reason for being there during the Trump Presidency," Trump wrote on Twitter. 

Leading Republican senators reacted with displeasure to the news.

Republican Sen. Lindsey Graham, typically a Trump backer, said he was "blindsided" by the report and called the decision "a disaster in the making." He said, "The biggest winners in this are ISIS and Iran."

Republican Sen. Marco Rubio of Florida said the withdrawal would be a "grave error with broader implications" beyond the fight against ISIS.

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Speaking to Dana Perino, Kinzinger - a member of the House Foreign Affairs Committee - said the move by Trump caught lawmakers and national security officials, including Defense Secretary James Mattis and Secretary of State Mike Pompeo, "off guard."

"I don't understand where this is coming from," he said. 

Kinzinger likened the withdrawal and Trump's proclamation to Barack Obama withdrawing U.S. troops from Iraq in 2011, allowing ISIS to form and grow in the ensuing years. He argued this will be a "devastating blow" to the fight against ISIS and it gives "huge impetus to Iran" to continue their presence in Syria. 

He said Trump's decision immediately followed a conversation with Turkish President Recep Tayyip Erdogan. 

"They're celebrating in Moscow and in Tehran right now. They're trembling in Tel Aviv and in Washington, we're confused because no one saw this coming."

Watch the full interview above.

AP contributed to this report.

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