WASHINGTON, US (AFP) - A US army psychiatrist who opened fire on fellow soldiers at Fort Hood Thursday, killing at least 11 people, had complained of harassment by his military colleagues, the man's cousin said.

"He was dealing with some harassment from his military colleagues," Nader Hasan told Fox News.

"I don't think he's ever been disenchanted with the military," he said of the shooter, who has been identified as Nidal Malik Hasan. "It was the harassment."