• Republican Sen. Susan Collins criticized President Donald Trump's decision to accept a jet from the royal family of Qatar, calling the transaction "rife with political espionage."
• Collins is the latest addition in escalating tensions from both sides of the aisle over the legality of accepting the $400 million gift.
• Trump has said the plane will be transferred to his presidential library foundation at the end of his second term.

Sen. of Maine on Thursday captured the growing sense of frustration among Republicans in Congress over President Donald Trump's plan to accept a $400 million from the royal family of to be converted into Air Force One.

"The transaction strikes me as being rife with political espionage, ethical and constitutional problems," Collins said in an interview with .

"The plane would have to be thoroughly scrubbed to ensure that listening devices had not been implanted. That would take a great deal of time, to make sure that it meets the security standards that the president needs," she added.

"Ultimately, I don't understand why we would pursue this for the new aircraft that the president needs."

Collins said that while she understands Trump's "frustration" with taking a long time to produce a new presidential plane, she does not think a gift jet is the right solution.

Trump's decision to accept the gift has over the legality, ethics and national security implications of what would be the largest foreign gift ever received by the U.S. government.

Earlier this week, Republican Sen. Ron Johnson, Wisc., called the gift "a very odd offer." Another Republican, Sen. Rand Paul, Ky., said on Fox News that he hopes the president will reject it.

Senate Democrats on Thursday introduced a joint resolution of disapproval to block a $1.9 billion arms sale to Qatar, in response to Trump's decision to accept the jet gift.

"This isn't a gift out of the goodness of their hearts – it's an illegal bribe that the President of the United States is champing at the bit to accept," Sen. Chris Murphy, Conn., said in a statement.

"That's unconstitutional and not how we conduct foreign policy. Unless Qatar rescinds their offer of a 'palace in the sky' or Trump turns it down, I will move to block this arms sale." The resolution was co-sponsored by Sens. Tim Kaine, Va., Chris Van Hollen, Md., and Brian Schatz of Hawaii. Joining them was Independent Sen. Bernie Sanders of Vermont.

On Tuesday, Senate Minority Leader Chuck Schumer, D-N.Y., announced that he is on Trump's nominees to the Department of Justice to protest the jet gift, calling it a "grave national security threat."

Trump has said the plane will be formally given to the U.S. Department of Defense, and then transferred to his presidential library foundation at the end of his second term. This way, the palatial jet is never owned personally by Trump.

Collins also questioned the timeline and necessity of Trump getting a new Air Force One, which may not even be finished with its retrofitting into a presidential plane by the time his term ends.

"This is complicated," she added.