WASHINGTON — Many church-affiliated institutions will have to cover free birth control for their employees, the Obama administration announced Friday in an election-year decision certain to upset conservatives and add to the national debate about the reach of government.

Granting a concession, however, Health and Human Services Secretary Kathleen Sebelius said nonprofit institutions such as church-affiliated hospitals, colleges and social service agencies will have one year more to comply with the requirement than most other employers.

'I believe this proposal strikes the appropriate balance between respecting religious freedom and increasing access to important preventive services,' Sebelius said in a statement.

That's unlikely to stop a determined effort by social conservatives to block or overturn the requirement.

The decision is 'a radical incursion into freedom of conscience,' said Deirdre McQuade, a spokeswoman for the U.S. Conference of Catholic Bishops. 'Never before in U.S. history has the federal government forced citizens to purchase directly what violates their beliefs.'

Officials said the administration's ruling was carefully considered, after reviewing more than 200,000 comments from interested parties and the public. The one-year extension, they said, responds to concerns raised by religious employers about the adjustments they would have to make. Administration officials stressed that individual decisions about whether or not to use birth control, and what kind, remain in the hands of women and their doctors.

Liberals praised the decision, saying that women who work for religious employers should not have to accept a lower standard of health insurance coverage.

'The administration stood firm,' said Nancy Keenan, president of NARAL Pro-Choice America. 'As a result millions will get access to contraception, and they will not have to ask their bosses for permission.'

Birth control use is virtually universal in the United States, and most health insurance plans cover the pill, usually with copays.

At issue is a provision of President Barack Obama's health overhaul law that requires insurance plans to cover preventive care for women free of charge to the employee. Last year, an advisory panel from the respected Institute of Medicine recommended including birth control on the list, partly because it promotes maternal and child health by allowing women to space their pregnancies.

Sebelius agreed, issuing a new federal regulation last summer.

That rule, however, exempted houses of worship and their employees, as well as other institutions whose primary purpose is to promote religious belief. Churches, synagogues, mosques and other places would not be required to cover contraceptives, it specified.