CHATTANOOGA, July 17 A 24-year-old gunman opened fire at two US military centres in Tennessee yesterday, killing four Marines in a rampage that officials said was being investigated as an act of “domestic terrorism.” The shooter — identified by the FBI as 24-year-old Mohammod Youssuf Abdulazeez — died in a firefight with police. Three people were injured — a police officer, a Marine Corps recruiter and a Navy sailor. The incident in the city of Chattanooga served as an ugly reminder of other deadly shootings at US military installations, including a 2009 rampage at Fort Hood in Texas that left 13 dead and a 2013 attack at the Navy Yard in Washington that left 12 dead. It also came amid fears about the threat posed by “lone wolf” attackers in the United States, though the motive in yesterday’s shooting was not immediately clear. President Barack Obama called the shootings “heartbreaking” and asked Americans to pray for the relatives of the victims. “It is incomprehensible to see what happened and the way that individuals who proudly serve our country were treated,” Chattanooga mayor Andy Berke said, praising the quick response by law enforcement to prevent further loss of life. “Today is a nightmare for the city of Chattanooga.” Bill Killian, the US federal prosecutor in that part of Tennessee, said the shooting was being treated as an “act of domestic terrorism.” “We are looking at every possible avenue — whether it was terrorism, whether it was domestic, international or whether it was a simple criminal act,” FBI special agent Ed Reinhold said. “We have no idea at this point what his motivation was behind this shooting,” Reinhold said. “At this point, we don’t have anything that directly ties him to an international terrorist organisation.” So far there has not been any indication that anyone else was involved in the shooting. US Attorney General Loretta Lynch said the FBI would take the lead in the “national security investigation of this heinous attack on members of our military.” Attacker from ‘average Chattanooga family’  CHATTANOOGA: Abdulazeez, a Muslim, lived in a leafy suburb of Chattanooga. US media reported that he was a naturalised US citizen born in Kuwait. The attack came just before the Eid al-Fitr holiday at the end of the holy Muslim fasting month of Ramadan. Abdulazeez graduated from the University of Tennessee at Chattanooga with a degree in engineering. “Sadly, it appears that the shooter was a 2012 graduate from UTC. Our thoughts are with those affected by today’s tragedy,” the university said on Twitter. A woman who attended Red Bank High School with Abdulazeez said he was a quiet kid, and well-liked. “He was friendly, funny, kind,” Kagan Wagner told the Chattanooga Times Free Press. “I never would have thought it would be him.” “They were your average Chattanooga family,” Wagner said. Scott Schrader, who coached Abdulazeez in mixed martial arts, told CNN he “seemed like the all-American kid.” In an apparent blog post written on Monday, Abdulazeez said Muslims should not let “the opportunity to submit to Allah... pass you by,” according to the SITE Intelligence Group, which monitors extremist activity on social media.