Two lawsuits have been filed by civil rights groups challenging US President Donald Trump's controversial ban on transgender people serving in the US military.
Both lawsuits say the ban violated US constitutional guarantees of equal protection and due process under the Fifth Amendment, and one said it also violates service members' free speech rights.
Mr Trump announced the ban in a series of Twitter posts on 26 July, reversing a policy of his predecessor, Barack Obama.
It halted years of efforts to eliminate barriers to military service based on sexual orientation or gender identity, including an "Open Service Directive" designed to let transgender people serve without fear of discharge.
When asked about the challenge, a White House official said: "we do not comment on active or pending litigation."
"President Trump cast aside the rigorous, evidence-based policy of the Open Service Directive, and replaced it with discredited myths and stereotypes, uninformed speculation, and animus against people who are transgender," according to one of the lawsuits, filed by the American Civil Liberties Union.
The ban was widely seen as an appeal by Mr Trump, a Republican, to his conservative political base.
Civil rights groups and some politicians from both the Democratic and Republican parties accused Mr Trump of politically motivated discrimination, and some senior military officials were caught off guard by the announcement.
Roughly 2,500 active duty personnel are transgender, according to a RAND Corporation study cited last year by Mr Obama's defense secretary, Ash Carter.
One lawsuit was filed in Baltimore federal court by the ACLU on behalf of six transgender people serving in several branches of the military.
The second lawsuit was filed in Seattle federal court by Lambda Legal and OutServe-SLDN on behalf of an Army staff sergeant, two transgender people who wish to join the military and various other groups.
