After years of debate and months of preparation, a 17-year-old US policy to ban gays and lesbians from serving openly in the military formally came to an end Tuesday.

President Barack Obama signed a legislation last December to repeal the policy, known as "Don't Ask, Don't Tell." But the repeal was not implemented until military service chiefs completed months-long training and preparation for lifting the ban.

"(The repeal) would enhance our national security, increase our military readiness, and bring us closer to the principles of equality and fairness," Obama said in a statement Tuesday.

Don't Ask, Don't Tell, which was introduced as a compromise measure in 1993 by then-President Bill Clinton, prohibited homosexuals from serving openly in the military. Civil rights activists have been fighting hard for years to end the policy.

"Statements about sexual orientation will no longer be a bar to enlisting in the military or a cause for dismissal," said Army Maj. Gen. Gary Patton, chief of staff for the Pentagon's repeal implementation team.

In addition, former service members separated from the military under Don't Ask, Don't Tell based solely on their sexual orientation will be eligible to reapply to return to military service.