(CNN) -- Two former Navy SEALs who were among four Americans killed last week in an attack on the U.S. Consulate in Benghazi, Libya, died after rushing to the aid of their colleagues, according to sources familiar with the incident.
Glen Doherty and Tyrone Woods were in Benghazi as part of a security contractor force.
On September 11, they were ensconced in the safety of an annex location in another part of the city when they got word that the main consulate building was under fire and the diplomats there -- with an armed force of only nine people -- were overwhelmed by the deteriorating situation.
Doherty and Woods, along with other security personnel, left the secure annex and made their way to the chaotic scene, rounding up the consulate staff who were under attack and guiding them back to the second safe building.
Their grim task also included recovering the body of computer expert Sean Smith, who had succumbed to smoke inhalation from a fire ignited by the attackers. The sources said diesel fuel was used to set the fire and the thick, black smoke created by the accelerant added to the confusion on the ground.
U.S. Ambassador Chris Stevens, who had gone missing during the attack, was not among those evacuated. He was later reported dead. The State Department has not released details about how Stevens died, though numerous media reports have said the ambassador was taken from the consulate to Benghazi Medical Center by locals.
After arriving back at the annex, the incident was far from over for the security team, which included Woods and Doherty. An attack was launched on the annex -- this one more intense than the initial assault on the main building.
Military officials in Benghazi told CNN that rocket-propelled grenades were among the heavy firepower used by the attackers at the annex, with one official saying mortars were also fired.
"It was during that (second attack) that two additional U.S. personnel were killed and two others were wounded," a senior administration official said last week in providing details of the attack. Those two victims were later confirmed to be Doherty and Woods.
The men were remembered last week during a transfer-of-remains ceremony attended by Secretary of State Hillary Clinton and President Barack Obama.
Doherty grew up in Massachusetts with a passion for the outdoors. He served two tours of duty in Iraq, starting with the U.S. invasion in 2003, before leaving the military in 2005. He then became a private security contractor, working in Afghanistan, Pakistan and Yemen. A diplomatic source told CNN that Doherty was in Libya to search for shoulder-fired anti-aircraft missiles -- a mission given high priority after the fall of longtime Libyan strongman Moammar Gadhafi.
Woods, a registered nurse and certified paramedic, served multiple tours in Iraq and Afghanistan. After retiring from the Navy, he worked in diplomatic security in posts from Central America to the Middle East.
"Four Americans, four patriots, they loved their country and chose to serve it and serve it well," Obama said. "They had a mission and they believed in it, and they knew the danger and they accepted it. They didn't simply embrace the American ideal, they lived it, they embodied it: the courage, the hope and, yes, the idealism."
CNN's Arwa Damon contributed to this report from Benghazi, Libya.