A coalition of more than a hundred Democratic members of Congress has asked Secretary of Defense Jim Mattis if the Pentagon helped advise President Donald Trump on his July decision to bar transgender Americans from serving in the U.S. military.

Led by Rep. A. Donald McEachin (D-Va.), 114 House members sent the letter asking the Pentagon to provide any information about correspondence between the White House and the Department of Defense regarding the controversial decision, which Trump made on Twitter and later via presidential memo.

“We seek access to these materials in order to determine whether the president, his national security team and military leaders are actively coordinating policy with one another, or whether the president’s transgender ban announced reflected a breakdown in communication,” the letter, dated Oct. 10, reads. “As you know, clear communication between the White House and the Pentagon is essential to our nation’s security.”

Trump reportedly surprised the Pentagon and “blindsided” his Joint Chiefs of Staff when he made the abrupt announcement. Gen. Joseph F. Dunford Jr. has publicly said he disagreed with the ban, telling the Senate Armed Services Committee last month that “any individual who meets the physical and mental standards” should be allowed to serve.

Mattis was given just a day’s notice about the decision, according to The New York Times.

“We seek information to discover the proof of where and when the Pentagon advised the president that this was the best idea for our country,” McEachin said in a news release Tuesday. “If there is proof then we can evaluate that, if there is no proof then the President lied to the American people once again.”

Several lawsuits have been filed challenging the ban, but the Trump administration has asked the court to dismiss one brought by transgender soldiers.

In his tweets, Trump said he had consulted “with my generals and military experts” to make the decision, saying “our military must be focused on decisive and overwhelming victory and cannot be burdened with the tremendous medical costs and disruption that transgender in the military would entail.”

A 2016 study by the RAND Corp. think tank found there were just 2,000 to 11,000 active-duty troops who are transgender and allowing them to serve openly would “have minimal impact on readiness and health care costs.” The report, commissioned by the Pentagon, estimated health care costs for such troops between $2.4 million and $8.4 million a year.

The Pentagon lifted its longtime ban on transgender service members in 2016 under former President Barack Obama.

Then-Defense Secretary Ashton Carter said at the time: “Our mission is to defend this country, and we don’t want barriers unrelated to a person’s qualification to serve preventing us from recruiting or retaining the soldier, sailor, airman or Marine who can best accomplish the mission.”