WASHINGTON — Nearly 70 civil rights and other organizations wrote to President Obama Tuesday, urging that he "reject calls to weaken" a planned executive order banning federal contractors from discriminating against LGBT workers by exempting "religiously affiliated contractors."

Among the signatories of Tuesday's letter are the Americans United for Separation of Church and State, Leadership Conference on Civil and Human Rights, and NAACP.

Notably in light of recent disagreements over the religious exemption in the Employment Non-Discrimination Act, pending in Congress, LGBT groups on both sides of that debate — from the ACLU and Lambda Legal to the Human Rights Campaign and National Center for Transgender Equality — signed on to Tuesday's letter.

"We urge you to act to prohibit any discrimination based on sexual orientation, gender identity, or religion with taxpayer funds by all federal contractors, including religiously affiliated organizations," the letter states.

Specifically, the groups state, "an exemption in this context would give a stamp of legitimacy to some types of discrimination that prior executive orders have never given to discrimination based on an individual's race, color, sex, or national origin."

The letter follows a series of letters sent to the president about the scope and presence of any religious exemption that might be contained in the forthcoming executive order. Most recently, on Monday, a group of 50 law professors sent a letter to Obama urging — similar to Tuesday's letter — that he not include a religious exemption in the order.