WASHINGTON — Pentagon officials will announce today that the ban on gays and lesbians serving openly in the armed services can be lifted without harming military readiness, a step that is likely to end the controversial "don't ask, don't tell" policy in September, Defense Department officials said.

Defense Secretary Leon E. Panetta and Adm. Mike Mullen, the chairman of the Joint Chiefs of Staff, are recommending to President Barack Obama that he proceed with final repeal of the policy in place for nearly two decades, the officials said.

Congress voted to repeal the 1993 "don't ask, don't tell" law last December, but delayed ending the ban until top Pentagon officials and the president could certify that the change would not adversely affect the military. Congress ordered that the ban cease to be enforced 60 days after the certification.

Repeal of the ban on gays and lesbians serving openly will be one of Panetta's first major acts since taking command of the Pentagon earlier this month. He replaced Robert M. Gates, who had called for eliminating the ban but pushed for a gradual process.

Panetta met recently with the chiefs of the Army, Navy, Air Force and Marines about lifting the ban, officials said.

Since the congressional vote to repeal the law, the military services have been training personnel on how to conduct themselves once the ban is lifted.