Roman Catholic groups on Thursday embarked on a two-week campaign of prayer vigils, rallies and other events to draw attention to what they consider government attacks on religious freedom.

Called the "Fortnight for Freedom," bishops organized the education campaign during liturgical feasts for martyred defenders of the faith. Independent advocacy groups such as CatholicVote.org and Women Speak For Themselves, have joined the effort with TV ads, videos, Facebook appeals and petition drives.

While the religious freedom campaign includes protests against state laws and policies, the bishops' immediate target is the mandate President Barack Obama announced in January that most employers provide health insurance that covers birth control. Federal officials said the rule was critical to women's health by helping them space out pregnancies.

Critics have accused the bishops of organizing the campaign as a partisan assault on Obama in an election year. But church leaders insist they have no partisan agenda and blame the timing on when federal officials approved the rule.