Mike Mullen, Robert Gates urge US senators to scrap the ban before year-end.
Unless the lame-duck Congress acts, repeal effort is considered dead for now.
US senators blocked an effort by Democrats to lift the ban on gays from serving openly in military.
Top US military officials urged Congress not to lift or ease a ban on gays serving openly in the armed forces until they have a strategy to address "concerns" about the move among troops.
A high-ranking US Army general won`t be formally reprimanded after urging troops to lobby to keep the ban on openly gay military service.
Lawmakers this week will press the military`s top uniformed officers for the first time on whether they think repealing "don`t ask, don`t tell" makes sense or would be too disruptive.
Democratic House Speaker Nancy Pelosi vowed on Thursday to find a way to end the ban on gays serving openly in the US military, a move facing stiff opposition from at least one White House ally.
Day in Pics: 23rd September
Showbiz World - September 23, 2014
'Kill Dil'- Posters