On a mission to bury the memory of Osama bin Laden by honoring those who died in the fiery Sept. 11, 2001, attacks, President Barack Obama on Thursday visited firefighters and police who lost colleagues at New York's Ground Zero and then laid a wreath at the site.

"When we say we will never forget, we mean what we say," he said in brief comments to the firefighters and others at the station he visited in New York's theater district. The station lost 15 men during the attacks.

In his brief remarks, the president never mentioned bin Laden's name.

"This is a symbolic site of the extraordinary sacrifice that was made on that terrible day," the president said Thursday at Engine 54, Ladder 4, Battalion 9.

At the First Precinct police station in lower Manhattan, the first on the scene on Sept. 11, Obama alluded to bin Laden's killing and said of those who died in the Sept. 11 attacks, "We keep them in our hearts. We haven't forgotten."

At Ground Zero, Obama laid the wreath at the foot of the so-called Survivor Tree, which sustained damage during the attack but was freed from the rubble.

The president closed his eyes and clasped his hands at the outdoor memorial where the twin towers of the World Trade Center once dominated the Manhattan skyline.