PHOENIX (Reuters) - An Arizona man was found guilty on Thursday (March 17) of plotting with others to attack a "Draw Muhammad" cartoon contest in Texas last year and providing material support to the Islamic State in Iraq and Syria (ISIS), prosecutors said.

Abdul Malik Abdul Kareem, 44, was convicted on all five charges against him by a federal jury in US District Court in Phoenix stemming from the May 3 attack in the Dallas suburb of Garland that left his two alleged associates dead in a shoot-out with the police.

The case against Kareem, also known as Decarus Thomas, was the first ISIS-related prosecution to reach trial of the dozens brought by the federal government across the nation.

It is the second jury verdict in such a case, as US Air Force veteran Tairod Pugh was convicted earlier this month in New York.

"This verdict sends a strong message to those who support terrorists," acting special agent in charge of the FBI's Phoenix division, Justin Tolomeo, said in a statement.

Kareem maintained his innocence and denied involvement in the attacks when he took the stand for two days in the federal trial.

His attorney Daniel Maynard said he was very disappointed with the verdict. "I obviously didn't do my job since I believe the jury convicted someone who is innocent," Mr Maynard said in an e-mailed statement to Reuters.

Kareem's roommates, Elton Simpson and Nadir Soofi of Phoenix, were killed by Garland police after they opened fire with assault rifles outside the May 3 cartoon drawing event.

The contest was intended to satirise Islam's Prophet Muhammad. It came months after gunmen killed 12 people in the Paris offices of French satirical magazine Charlie Hebdo in what was said to be revenge for its cartoons depicting Prophet Muhammad.

Such portrayals are considered offensive by Muslims. None of the approximately 150 people attending the event in Garland in May were hurt.

The original indictment said Kareem supplied the two gunmen with arms and helped them prepare for the attack.

He was later charged with showing support for ISIS in social media posts, researching travel to the Middle East to train with terrorists and seeking to make explosives that could be used during last year's Super Bowl in Arizona, the most-watched US sporting event annually.

Prosecutors said Kareem could face a potential sentence of at least 45 years in prison.