JACKSONVILLE, Fla. -- President Barack Obama thanked about 3,500 sailors, Marines and soldiers Monday afternoon for their service during remarks at Naval Air Station Jacksonville, promising them: "I won’t risk your lives unless it is absolutely necessary."

Obama's appearance, the first stop of a two-day trip to Florida, included a tribute to the Americans who continue to lose their lives in service to their county.

"We're reminded of this again with today's helicopter crashes in Afghanistan. Fourteen Americans gave their lives, and our prayers are with these service members, their civilian colleagues, and the families who loved them," Obama said. "We have the finest Navy and the finest military in the history of the world because we have the finest personnel in the world. You are the best trained, the best prepared, the best led force in history. Our people are our most precious resource."

The remarks have added significance as Obama has been asked by the Pentagon to commit thousands of more troops in Afghanistan.

Obama also remembered a Navy pilot shot down over Iraq in 1991.

"Navy Capt. Michael Scott Speicher. The kid from Orange Park. Loving husband. Devoted father. Based at Cecil Field, not far from here. Then, on the first day of Operation Desert Storm, he was taken from us," Obama said. "In the long years that followed, a Navy family and this city would endure the heartache of the unknown."

Obama acknowledged the long, unbroken line of naval aviators from Jacksonville, including his political rival, Sen. John McCain, who a pilot who was based at Cecil Field prior to being deployed to Vietnam, shot down and taken prisoner of war.

The audience included Navy sailors assigned to units at NAS Jacksonville; the Coast Guard, Army, National Guard and reserve personnel; sailors from Mayport, Fla., and Kings Bay, Ga; and Marines from Blount Island.

The audience gave the president a warm reception, especially when he discussed increasing military pay and more funding for health care and GI bill benefits.

Obama took the podium just before 3:30 p.m., about 15 minutes later than scheduled, and spoke for nearly 20 minutes. After his remarks, he went into the crowd and shook hands and signed autographs among dozens of the servicemen and women who attended.

Florida's Democratic Sen. Bill Nelson, as well as Rep. Corrine Brown, D-Jacksonville, and Ander Crenshaw, R-Jacksonville, accompanied the president on Air Force One on the flight to Jacksonville

This is Obama's first visit to Jacksonville since the morning before Election Day last November, which he began with a rally at Veterans Memorial Arena.

On the tarmac before heading back to Air Force One, Obama approached some children watching all the activity.

"We're the luckiest kids in the world," Matthew Reger said after Obama shook hands with him and his brother.

By 4:30 p.m., Obama took off for Miami for a congressional fundraiser in the evening. Obama is scheduled to visit a solar energy center in Arcadia at midday on Tuesday before traveling to Norfolk, Va., for remarks at Old Dominion University before returning to the White House that night.