The Pentagon announced on Thursday that transgender individuals are now able to serve openly in US armed forces.

"Effective immediately, transgender Americans may serve openly, and they can no longer be discharged or otherwise separated from the military just for being transgender," said US defense chief Ash Carter here at a press conference.

"Americans who want to serve and can meet our standards should be afforded the opportunity to compete to do so," said Carter, adding that the policy will be phased in during a one-year period.

According to 2014 study by RAND Corporation, about 2,500 people out of roughly 1.3 million US active-duty service members, and about 1,500 out of 825,000 reserve service members are transgender.

The end of the ban on transgender service was the latest step by the Pentagon to be more inclusive. So far, the US military has also ended the ban on gays serving openly and opened all combat jobs to women.