US bishops have expressed disappointment over President Donald Trump's decision not to revoke an executive order, introduced by Obama, which bans discrimination on the basis of sexual orientation and gender identity against federal employees.

Trump's action is "troubling and disappointing", said Archbishop Charles Chaput of Philadelphia, chairman of the US Conference of Catholic Bishops' Committee on Laity, Marriage, Family Life and Youth, and Archbishop William Lori of Baltimore, chairman of the USCCB Ad Hoc Committee for Religious Liberty.