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 planned to announce his decision today in the Oval Office, a White House official said yesterday, speaking on the condition of anonymity because the president hadn't yet signed the presidential memorandum.

The decision is a political nod to a reliably Democratic voting bloc that 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 at which 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.

Gays and lesbians 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.

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. *