Chattanooga (United States) (AFP) - The death toll in the mass shooting of US military personnel in Tennessee rose to five Saturday as investigators pursued the motive behind the rampage.
In a brief statement, the US Navy said a petty officer succumbed overnight to wounds he sustained in Thursday's attack on two military centers in Chattanooga.
The Navy did not identify the sailor, but relatives named him as Petty Officer Randall Smith, a father of three daughters who had recently re-enlisted and transferred to Chattanooga.
"It's hard to understand how somebody can hurt somebody that's serving for you, for your freedom, for your safety," his step-grandmother Darlene Proxmire told WANE television in Indiana.
Four Marines also died in the attack -- which authorities are treating as "an act of terrorism" -- before the gunman, Mohammad Youssuf Abdulazeez died in a shootout with police.
The FBI has asked foreign intelligence agencies to help trace Abdulazeez's movements and activities abroad, and analysts are monitoring his activity on social media.
The 24-year-old was a naturalized US citizen born in Kuwait.
"Every one of our resources are being devoted to this investigation," Chattanooga Mayor Andy Berke told CNN.
But the FBI warned against jumping to conclusions, after Michael McCaul, chairman of the House of Representatives Homeland Security Committee, branded the assault "an ISIS-inspired attack."
"At this time, we have no indication that he was inspired by or directed by anyone other than himself," FBI special agent Ed Reinhold said, referring to Abdulazeez.
"We obviously want to know what his thoughts were and who else he was associating with."
The shooting has jarred the city of 168,000, where the Islamic Society of Greater Chattanooga condemned the attack and cancelled its end-of-Ramadan Eid al-Fitr celebrations out of respect for the victims.
- Troubled past? -
Going into the weekend, more details about Abdulazeez -- a University of Tennessee engineering graduate and mixed martial arts enthusiast who grew up in a middle-class neighborhood -- slowly emerged.
Investigators were looking at Abdulazeez's foreign travel, with a reported trip to Jordan last year of particular interest.
There was evidence, however, that he came from a troubled family. Divorce papers filed by his mother alleged that his father beat his wife and five children.
The father was also reportedly investigated for ties to a terrorist group, but ultimately was cleared.
Abdulazeez's only known brush with the law was in April, when he was arrested for driving under the influence.
He briefly worked at a nuclear power plant in Ohio in May 2013, but was fired after failing to meet minimum employment requirements, a spokeswoman for Perry Nuclear Power Plant operator FirstEnergy said.
In Washington, Defense Secretary Ashton Carter has asked for recommendations on how to boost security for troops and civilians at military installations.
But state governors in Arkansas, Florida, Indiana, Louisiana, Oklahoma and Texas signed executive orders that would allow US military personnel to carry firearms at recruiting centers.
Such facilities are often located in shopping malls, with no special security measures and recruiting staff inside unarmed.
"After the recent shooting in Chattanooga, it has become clear that our military personnel must have the ability to defend themselves against these type of attacks on our own soil," Texas Governor Greg Abbott said.
Republican presidential hopefuls Jeb Bush, Donald Trump and Scott Walker called for the lifting of a prohibition on military personnel carrying firearms at recruiting venues.