Hundreds of pro-life activists from across the country are converging on Notre Dame's bucolic campus with one purpose in mind: to protest President Obama.

The university's decision to invite the president, who supports abortion rights, to deliver the commencement address Sunday and to award him an honorary degree has brought protesters to South Bend, Ind., by the busload with their protest signs, some displaying the message "Obama = Abortion" and others showing images of aborted fetuses.

As more than 2,000 students prepare for their graduation ceremony, members of the Pro-Life Action League and Citizens for a Pro-Life Society said they'll congregate at 10:30 a.m. Sunday just off-campus in opposition to the president's support of abortion rights and embryonic stem-cell research.

"I'm going to Notre Dame to be a witness to the truth," Mary Sullivan, a member of Citizens for a Pro-Life Society, told FOXNews.com. "As a Catholic, this is not what the church teaches and it slaps in the face of what Catholics believe. We don't believe in using fetuses to supposedly find cures for diseases."

Sullivan, who lives in the Detroit suburb Southfield, Mich., will board a 56-seat bus in Ann Arbor along with her husband and two neighbors to make the trip to South Bend. Another bus, meanwhile, will leave from Detroit.

"My purpose of going is I will pray and meditate," Sullivan said. "And I will pray that people will hear the truth and understand what's going on here. We're trying to change hearts and get people to understand that this truly is intrinsic evil."

Judy Parran, an organizer for the group, said a third bus is currently being procured due to increasing demand. Several priests and nuns are expected to be on board, she said.

"The calls just keep on coming," Parran told FOXNews.com. "I just got an e-mail from a couple of people who aren't even Catholic."

Corrina Gura, an organizer for the Pro-Life Action League, said their group will send a total of four buses -- approximately 220 people.

"A lot of people have told us they're driving separately as well," she said. "People are asking if we're adding other buses."

Pro-Life Action League members also will begin their civil disobedience effort off-campus and then join the Citizens for a Pro-Life Society at the prayer vigil on campus to coincide with the commencement ceremony. Additional arrests are possible, if not expected.

"We're going have graphic pictures of abortion and what abortion does to babies and we'll also have signs that will say 'Obama = Abortion' and 'Shame on Notre Dame,'" Gura said.

Citizens for a Pro-Life Society will be carrying signs ranging from the "very graphic to very simple," Parran told FOXNews.com.

The two groups' approach will differ drastically from that of ND Response, a coalition of student groups that plan to voice their opposition to President Obama with peaceful protest and no graphic signs, beginning with an all-night vigil late Saturday and another vigil on Sunday.

And despite calls from ND Response for the two groups to hold orderly demonstrations, some protesters haven't gotten the message and plan on being escorted off campus in handcuffs.

One of those dissidents is Norma McCorvey, the plaintiff in Roe v. Wade, which legalized abortion in all 50 states in 1973. McCorvey, a born-again Christian who runs Roe No More Ministry in Dallas, flew to South Bend, Ind., on Friday.

"I'm coming because I want to show Mr. Obama that I'm not in favor his pro-abortion stance," McCorvey told FOXNews.com prior to boarding a connecting flight in Cincinnati, Ohio. "I'm a peaceful protester, but if they come and take me away, they'll just come and take me away."

McCorvey said she's especially excited for a meditation to be held by the Rev. Frank Pavone, national director of Priests for Life, during Obama's commencement address and the candlelit vigil led by Rev. John D'Arcy, bishop of the Fort Wayne-South Bend diocese who will not attend Sunday's graduation, in protest of the president.

"Hopefully we can convince Mr. Obama that he should be standing on the right side, and that's the side for life," she said. "I'm pro-life now, I'm not afraid."

Asked what she'd say to President Obama if given the opportunity, McCorvey replied, "I can't talk like that anymore. I'm a Christian."