The headquarters of a pro-life organization in Madison, Wisconsin, was set on fire in an apparent arson attack, police said Sunday.

The Madison Police Department said flames were seen coming from the offices of Wisconsin Family Action in the city's north side shortly after 6 a.m. Sunday. The fire was quickly put out by the Madison Fire Department. No one was hurt, police said.

"A molotov cocktail, which did not ignite, was thrown inside the building. It also appears a separate fire was started in response," a police report said.

Arson investigators are working with fire department officials to determine an exact cause.

Media reports said the outside of the building also sprayed with graffiti depicting an anarchy symbol, a coded anti-police slogan and the phrase, "If abortions aren't safe then you aren't either."

Bishop Daniel Hying of Madison tweeted a news report on the incident Sunday afternoon.

Representatives of Wisconsin Family Action were not immediately available for comment Sunday. The organization's website says the group advocates for the unborn, traditional marriage, and religious liberty.

"Please keep our friends at Wisconsin Family Action/Wisconsin Family Council in your prayers," Wisconsin Right to Life said in a Facebook post Sunday. "Thankfully, no one was hurt in the attack on their Madison office this morning.

WFA President Julaine K. Appling told News 3 Now said that someone had thrown Molotov cocktails into her office and had burned books.

“We get veiled and not so veiled threats from time to time,” Appling told the television station. “We’ve never had anything that materialized like this."

Appling told the station that she respects others' right to disagree with her organization's positions, but not when it comes to acting out violently.

“We can all disagree,” she said. “People disagree with me all the time. I don’t go threaten them.”

The attack in Madison came during a tense weekend in the wake of a pro-abortion group's threat to disrupt Masses at Catholic churches on Sunday, which was Mother's Day. There were no major disruptions at churches reported as of 5:30 p.m. EDT Sunday. The group Ruth Sent Us made the threat after the leak of a preliminary draft opinion in a Mississippi abortion case that suggested that a conservative majority on the court is poised to overturn the landmark abortion decision Roe v. Wade.