Dozens of retired generals and admirals have come out against President Donald Trump's decision to bar transgender people from serving in the military.

Fifty-six retired military leaders on Tuesday joined in condemning the proposed policy change, saying that it would “cause significant disruptions” and “deprive the military of mission-critical talent.”

In a series of tweets last week, Trump declared that the military will no longer “accept or allow” transgender troops to serve “in any capacity.” The president said that the ban was needed to avoid “tremendous medical costs and disruption” posed by transgender people serving in the military.

The retired generals and admirals disagreed, citing research showing that medical costs would amount to just “one-hundredth of one percent of the military's health care budget.”

“President Trump seeks to ban transgender service members because of the financial cost and disruption associated with transgender service,” the retired military leaders wrote. “We respectfully disagree, and consider these claims to be without merit.”

General Joseph Dunford, the chairman of the Joint Chiefs of Staff, has said that “no modifications” to the policy will be implemented until the secretary of defense has issued implementation guidance.

(Related: Pentagon: No official change has been made on transgender service.)