World Bulletin / News Desk 

Two suspects were shot dead on Sunday in the U.S. state of Texas after they opened fire outside a contest for cartoons depicting Prophet Muhammad, authorities said.

Police put the Curtis Culwell Center in the city of Garland on lockdown and evacuated the event’s participants, the city said in a Facebook post. Several surrounding businesses were also evacuated.

One security officer suffered non-life-threatening injuries during the incident, the city said. He was treated and released, according to local media.

The event, billed as the "Muhammad Art Exhibit and Cartoon Contest," was sponsored by the New York-based anti-Muslim, pro-Israel American Freedom Defense Initiative group.

The group recently sparked controversy when it placed Islamophobic advertisements on transit systems of a number of major U.S. cities, including New York, Washington and Philadelphia.

It was not immediately clear whether Sunday's shooting was related to the event.

"Garland Police are asking people to avoid the area of the Culwell Event Center in North Garland," police said on Twitter.

Law enforcement officers extended a perimeter 2,000 feet around the center and a bomb squad was on the scene investigating a car within that zone, the Dallas Morning News reported.

"We were prepared for something like this," police spokesman Joe Harn said.

The gunmen's identities were not immediately released.

Dutch anti-Islamic politician Geert Wilders was also attending the event.

The anti-Islamic contest would award $12,500 for the “best cartoon” depicting Prophet Muhammad, a derogatory practice that has often offended Muslims across the world.