RALEIGH, N.C. — Republican incumbent Richard Burr launched his first television attack ad against Democratic challenger Deborah Ross Tuesday as their U.S. Senate race intensified, accusing her of opposing North Carolina’s sex offender registry as a civil rights lobbyist.

Ross immediately pushed back on the airwaves against the two-term U.S. senator.

Burr’s statewide campaign commercial accuses Ross of opposing the registry as it passed the General Assembly in the 1990s, when she worked with the American Civil Liberties Union. It features a Marine Corps veteran who says she was raped.

Ross “wants to protect sexual predators over victims,” Kelly Lowe of Onslow County says in the ad. “When they choose to rape, they don’t get those rights back.”

These accusations aren’t new, and Ross has raised enough money to fight back. Her own commercial was up and running within hours, featuring former Sen. Fountain Odom, a chief sponsor of the registry laws passed in 1995 and 1997.

“Sen. Burr is flat out lying and that’s why people hate politics,” Odom says. “Deborah not only supports the sex offender registry, she worked to make it stronger.”

Burr and his allies have long cited Ross’ efforts to shape the registry law as evidence that she’s too radical for the state’s voters. Going on TV about it appears to affirm that Burr believes it’s a winning issue.

It also reflects the tightness of his race with Ross, who served 10 years in the legislature after her time with the ACLU. Several recent polls have shown the race as statistically even.

The Associated Press typically does not identify alleged victims of sexual assault, but Lowe has identified herself publicly in the ad and at sexual assault awareness events.

The General Assembly established the registry in 1995, requiring people convicted of certain sex crimes to account for themselves with the sheriff in the county where they lived. Burr’s ad cites a memo Ross wrote to ACLU leaders then, predicting it “would make it even harder for people to reintegrate into society and start over and could lead to vigilantism.”

Ross also questioned whether victims of sex offenses by a family member would be wrongly identified. The legislature moved in 1997 to make sex offenders’ names and addresses accessible to the public on the internet.

Other newspaper reports from 1998 and 2000, cited by Burr’s campaign, quote Ross as still having concerns about the registry.

“I wanted a sex offender law that would stand the test of time, not get struck down as unconstitutional and not re-victimize the victim by publicizing where they lived,” Ross told The Associated Press in an interview last February.

Ross’ campaign said she voted to improve and update the registry 18 times while representing Wake County from 2003 to 2013.

“Just because someone raises questions about a law,” Ross told AP, “doesn’t mean that you want the whole thing to go away.”

The Senate Leadership Fund, a super PAC seeking to help keep the U.S. Senate in GOP hands, has said it will spend $8.1 million on ads in the North Carolina race. Its latest ad also came out Tuesday and also criticizes Ross on the registry, as well as another law she voted against that the ad says reflects her “left-wing politics.”

Fund spokesman Ian Prior said there was no coordination between his group and Burr’s campaign. Working in tandem would be unlawful.

Ross’ campaign separately accused Burr of voting against bills that contained funds designed to protect children and prosecute child sexual predators.