DALLAS – Texas police killed two gunmen who opened fire at an exhibit of caricatures of  Prophet Mohammad organized by an anti-Islamic group, authorities said on Sunday.

Sunday’s attack took place shortly before 7 p.m. in a parking lot of the Curtis Culwell Center, an indoor arena in the suburb of Garland, northeast of Dallas. Geert Wilders, a polarizing Dutch politician and anti-Islamic campaigner who is on a jihadist hit list, was among speakers at the event. 

Police said they had not immediately determined the identity of the two gunmen or whether they were linked to critics of the event who had branded it anti-Islamic.

As a precaution, police were examining the suspects’ car for any explosives that might be in the vehicle, Harn added.

The exhibit was organized by Pamela Geller, president of the American Freedom Defense Initiative (AFDI). Her organization, which is described by the Southern Poverty Law Center as a hate group, has sponsored anti-Islamic advertising campaigns in transit systems across the country.

Organizers said the exhibit was an event to promote freedom of expression. They offered a $10,000 prize for the best artwork or cartoon depicting the Prophet, as well as a $2,500 “People’s Choice Award.”

Depictions of the Prophet are viewed as offensive in Islam, and Western art depicting the Prophet has sometimes angered Muslims and provoked threats from radicals. Charlie Hebdo, the French magazine attacked in January, had printed cartoons of the Prophet.

In Sunday’s incident, the two armed suspects drove up to the front of the building in a car as the event, billed the “Muhammad Art Exhibit and Contest,” was coming to an end, and began shooting at a security officer, striking him in the leg, police and city officials said.

Garland police officers who were on the scene assisting with security then exchanged fire with the gunmen, and both suspects were shot dead, Harn said.

The security officer was treated at a local hospital and later released, he said. No one else was injured.

Most of the people attending the event were still inside the arena when the violence unfolded and were unaware of what had occurred until police came into the building and advised everyone to remain indoors because of a shooting.

“The first suspect was shot immediately. The second suspect was shot and wounded – reached for his back pack. Of course officers not knowing what was in the backpack, shot him again. He was killed,” Garland Mayor Douglas Athas told CNN.

Geller, who is known for her stance on Islam, said on Fox News that she chose the Garland venue for the art exhibit because it was where American Muslim leaders held a conference on combating Islamophobia a week after the Charlie Hebdo attacks.

In 2010, Geller led a march to the site of a proposed Islamic center near the site of the destroyed World Trade Center.

In response the shooting in Garland, the AFDI issued a statement on Facebook saying, “This is war on free speech. What are we going to do? Are we going to surrender to these monsters?”

In his speech at the event, shown in a video clip posted on AFDI’s website, Dutch politician Wilders offered his rationale for supporting the cartoon contest, saying depicting the Prophet and violating one of Islam’s greatest taboo was a liberating act.

“Our message today is very simple: we will never allow barbarism, never allow Islam, to rob us of our freedom of speech,” he told the audience.