Donna Cassata

Associated Press

A House Republican candidate is using video footage moments before the beheading of American James Foley in a campaign ad slamming Arizona Democratic Rep. Kyrsten Sinema as weak on national security.

Retired Air Force Lt. Col. Wendy Rogers launched the commercial that opens with a member of the Islamic State group with a knife as Foley kneels, an image directly from video footage released by the militants on Aug. 19. The spot does not show the beheading.

"Terrorist threats are growing. Are we secure? Are we protected?" an announcer says as other images of ISIS are shown. "Keeping us safe and secure is Congress' job. Kyrsten Sinema hasn't done her job. … She's allowed her liberal agenda to get in the way of our safety."

Republican candidates have criticized Democrats as soft on terrorism using images of members of militants from ISIS carrying a black banner. The Rogers ad marked the first time that video footage of the beheading showed up in an ad, prompting Democrats to demand that Rogers take the commercial off the air.

"It is reprehensible and unbecoming of anyone seeking elected office to use the footage of an American tragedy for political gain, and Wendy Rogers should remove this ad immediately and apologize to Mr. Foley's family," said Tyrone Gale, a spokesman for the Democratic Congressional Campaign Committee. "For Wendy Rogers to use such a reprehensible tactic to make baseless claims just to smear Representative Sinema proves how desperate her campaign has become."

Rogers' campaign spokesman, James Harris, defended using the footage, saying it was a fair use of current-affairs scenes to highlight differences between the candidates.

"We think it's an important ad to highlight the differences on what this election is about and how President Obama's failed leadership internationally has made our country less safe," he said.

Sinema referred questions to her campaign staff, and they were not able to comment immediately.

Rogers has purchased about $124,000 worth of ad time to air the commercial in the Phoenix market and on cable, according to ad buys.

Although Sinema narrowly won her seat in 2012, she is considered a favorite to win re-election.