WASHINGTON (KDKA/AP) – A group of 50 former GOP national security officials has signed an open letter opposing Republican presidential nominee Donald Trump.

Those who signed worked for former Presidents Richard Nixon, Ronald Reagan, George H.W. Bush and George W. Bush and say they are convinced that Trump would be “the most reckless president in American history.”

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The letter is similar to one issued by some of the same Republican former officials and foreign policy experts in March. The letter released Monday does contain some new names, however, including former U.N. Ambassador John Negroponte, former CIA director Michael Hayden and former Secretary of Homeland Security Tom Ridge, who is also a former Governor of Pennsylvania.

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None of the living former Republican secretaries of state signed the letter, although Condoleezza Rice’s ex-chief of staff, Brian Gunderson, is among the signatories.

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One official who signed the letter reportedly told CNN that most signatories travel abroad and interact with current and former world leaders. Many were alarmed at how many world leaders said they were concerned that Trump’s “recklessness” would invite America’s enemies to be even more reckless.

This official said he was stunned by how “enthusiastic” everyone was to sign.

Trump’s campaign responded with a statement from denouncing those who signed the letter as people who deserve the “blame for making the world such a dangerous place.”

(TM and © Copyright 2015 CBS Radio Inc. and its relevant subsidiaries. CBS RADIO and EYE Logo TM and Copyright 2015 CBS Broadcasting Inc. Used under license. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. The Associated Press contributed to this report.)

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