Garland Police Department officers fired back at the gunmen, who were both shot and killed, the statement said.
Two armed men were killed after opening fire on a security officer working outside of a Dallas center where a controversial art event featured cartoons depicting the Prophet Muhammad, authorities said Sunday.
The officer, Bruce Joiner, 58, was treated at a local hospital and released about two hours later, KXAS-TV reported.
The two men drove up to the Curtis Culwell Center and began shooting at a security officer, according to a statement that the city of Garland posted on its Facebook page Sunday night.
Garland Police Department officers fired back at the gunmen, who were both shot and killed, the statement said.
The statement doesn't say if the shooting was related to the controversial event.
A bomb squad was on the scene after authorities fear the gunmen's vehicle contained an "incendiary device."
As today's Muhammad Art Exhibit event at the Curtis Culwell Center was coming to an end, two males drove up to the front...
Posted by City of Garland, Texas Government on Sunday, May 3, 2015
An evacuation was ordered of nearby businesses.
The exhibit was hosted by the American Freedom Defense Initiative, which offered $10,000 for the best cartoon depicting the Prophet Muhammad.
USA Today notes that any drawings -- even a respectful one -- of the Prophet Muhammad are considered blasphemous by many followers of Islam and have sparked violence around the world.
Earlier Sunday, about 75 attendees at the contest were escorted by authorities to another room in the conference center. They were then taken to a separate location, where an Associated Press reporter was told they could not leave until FBI agents arrived to question them.
Johnny Roby of Oklahoma City, Oklahoma, was attending the conference. He told the AP he was outside the building when he heard around about 20 shots that appeared to be coming from the direction of a passing car.
Roby said he then heard two single shots. He said he heard officers yell that they had the car before he was sent inside the building.
Pamela Geller, president of the AFDI, told the AP before Sunday's event that she planned the contest to make a stand for free speech in response to outcries and violence over drawings of Muhammad.
In January, 12 people were killed by gunmen in an attack against the Paris office of the satirical newspaper Charlie Hebdo, which had lampooned Islam and other religions and used depictions of Muhammad.
Though it remained unclear several hours after the shooting whether it was related to event, she said Sunday night that the shooting showed how "needed our event really was."
Geller's group is known for mounting a campaign against the building of an Islamic center blocks from the World Trade Center site and for buying advertising space in cities across the U.S. criticizing Islam.
The Associated Press contributed to this report.