WASHINGTON -- President Obama, under growing criticism for not seeking to end the ban on openly gay men and women in the military, is extending benefits to same-sex partners of federal employees.

Obama plans to announce his decision on Wednesday in the Oval Office, a White House official said Tuesday. The official spoke on the condition of anonymity because the president hadn't yet signed the presidential memorandum.

The official said Obama would release more details on Wednesday.

The decision is a political nod to a reliably Democratic voting bloc that in recent weeks has grown frustrated with the White House's slow movement on their priorities.

Several powerful gay fundraisers withdrew their support from a June 25 Democratic National Committee event where Vice President Joe Biden is expected to speak. Their exit came in response to a June 12 Justice Department brief that defended the Defense of Marriage Act, a prime target for gay and lesbian criticism. Justice lawyers argued that the law allowed states to reject marriages performed in other states or countries that defy their own standards.

The legal arguments -- including citing incest and sex with minors -- sparked rebellion among gay and lesbian activists who had been largely biting their tongues since Obama won election. They had objected to the Rev. Rick Warren's invitation to participate in the inauguration despite his support for repealing gay marriage in California.

Their January protest won the invitation of Episcopal Bishop V. Gene Robinson, whose consecration as the first openly gay bishop divided and almost split his denomination.

Gays and lesbians later fretted as the White House declined to intervene in the cases of enlisted military members facing courts martial for defying the Clinton-era "don't ask, don't tell" policies. White House officials say they want Congress to repeal the policy as part of a "lasting and durable" solution, instead of intervening on individual cases.

"The president agreed that ... the policy wasn't working for our national interests, that he committed to change that policy, that he's working with the secretary of defense and the joint chiefs on making that happen," White House spokesman Robert Gibbs said last month.

In the meantime, the administration has tried to make small, quiet moves to extend benefits to gays and lesbians. The State Department has promised to give partners of gay and lesbian diplomats many benefits, such as diplomatic passports and language training.

But without a specific change in the Federal Employees' Health Benefits Program, Secretary of State Hillary Rodham Clinton's promises left out financial benefits such as pensions. Obama's move could make that shift.

Gay and lesbian activists had expected Obama to take action some time in June, which is gay pride month.

John Berry, the highest-ranking gay official in the administration and the de facto human resources chief for the administration, told a gay rally last weekend that Obama planned to take action on benefits soon.

Berry, who heads the Office of Personnel and Management, has repeatedly told reporters that he expected the White House to turn to legislation to give domestic partners access to federal health and retirement plans.

But Obama so far has sent only one piece of legislation to the Hill -- a pay-as-you-go measure that is part of his wooing of fiscally conservative Democrats.

Instead, Obama will use his signature instead of legislation to achieve the benefits parity sought by same-sex couples.