Atlanta Archbishop Wilton D. Gregory is urging area Catholics to press their elected officials to reverse a federal mandate that requires church-affiliated institutions to offer health coverage that includes birth control services.

On Sunday, area priests read a letter to parishioners during masses, in which Gregory called the decision a "direct attack on our religious freedom and our First Amendment rights."

"As a result, unless the rule is overturned, we Catholics will be compelled either to violate our consciences, or to drop health coverage for our employees (and suffer the penalties for doing so)," Gregory said in the letter. "The administration’s sole concession was to give our institutions one year to comply.”

At issue is a requirement for health coverage that would include preventive services such as contraception or sterilization. According to U.S. Department of Health and Human Services Secretary Kathleen Sebelius, women will not have to "forego these services because of expensive co-pays or deductibles, or because an insurance plan doesn’t include contraceptive services. "

HHS said the rule is in line with many states that already require contraception coverage in health plans. Nonprofit employers, who do not currently provide contraceptive insurance coverage based on religious beliefs, will have until Aug. 1, 2013, to comply with the new regulations.

Although the mandate doesn't apply to churches, it does affect affiliated colleges, schools, social service agencies and hospitals.

"Obviously, it strikes at the heart of our Catholic identity," said Joseph Krygiel, CEO of Catholic Charities Atlanta, a social services agency. The agency, which operates under the auspicies of the the Atlanta Archdiocese, employs about 70 people. Krygie worries that in the long run, using an alternative health provision could cost employees more.

"I think it's an attack on our religious freedom," he said. "In the past, any religious institution -- not just Catholic -- received an exemption. We don't understand why this can't be the case now. This is completely unacceptable."

The Rev. Jack Durkin, pastor of  St. Monica Catholic Church in Duluth, agreed. He said the measure goes against the Catholic position on contraception, adding, "We see this as not only opposing our morals and teachings but also opposing what is good for human persons."

He said Catholic teaching calls for a natural family planning that "we should be able to practice freely ... The government shouldn't be telling us to do something that we see as opposing health on a physical level, an emotional level and a psychological level. We see it as offensive to even offer something like that."

Bill Garrett, chief mission officer at St. Joseph's Health System, which has 3,000 employees, called the regulations a "clear violation" of freedom of religion and conscience.

"We will be seeking the one-year waiver from implementation of these changes," he said. "During the year we will observe what the courts conclude about this change in regulations."

The Associated Press contributed to this article.