President Barack Obama smiles as he stands with Prime Minister Mehdi Jomaa of Tunisia after speaking to the media in the Oval Office of the White House, Friday, April 4, 2014, in Washington. (AP Photo/Carolyn Kaster)

WASHINGTON -- President Barack Obama on Monday will sign an executive order banning workplace discrimination against gay, lesbian, bisexual and transgender workers of federal contractors and the federal government.

The executive order has two components: It prohibits federal contractors from discriminating against employees based on sexual orientation or gender identity -- a move that affects 24,000 companies employing roughly 28 million workers, or about one-fifth of the nation's workforce -- and it explicitly bans discrimination against federal employees based on their gender identity.

Senior administration officials outlined details of the executive order in a Friday afternoon call.

To the relief of the LGBT community, there is no sweeping religious exemption in the executive order. Obama is simply adding the categories of sexual orientation and gender identity to an existing executive order that protects employees of federal contractors from discrimination based on race, color, religion, sex or national origin. President George W. Bush amended that executive order in 2002 to allow religiously affiliated federal contractors to prioritize hiring employees of their particular religion, however, and Obama is keeping that language intact.

"Obama's executive order does not modify that Bush exemption," said a senior administration official. "It stands."

The president vowed during his 2008 campaign to take action on discrimination among federal contractors, and LGBT rights groups have been urging him to do so ever since, to no avail. The White House has focused instead on pressuring Congress to pass the Employment Non-Discrimination Act, which would have much broader implications. But that bill has stalled, and in the meantime, pressure has grown on the president to act in ways that don't require legislative approval.

The piece of the executive order targeting federal employees, meanwhile, responds to what some have described as a shortcoming in existing governmental rules. The Equal Employment Opportunity Commission ruled in 2012 that the federal ban on sex discrimination covers transgender discrimination, but those affected by that rule change say the government hasn't been enforcing it and that they continue to be discriminated against.

Once Obama signs the executive order, the provision affecting federal employees takes effect immediately, per the official. The provision affecting federal contractors will take effect early next year.