JACKSONVILLE – President Barack Obama mourned 14 Americans killed Monday in helicopter crashes in Afghanistan and told a military audience he will not be hurried as he evaluates whether to alter U.S. strategy in the war.

“I will never rush the solemn decision of sending you into harm’s way. I won’t risk your lives unless it is absolutely necessary,” Obama said during a visit to Naval Air Station Jacksonville.

Obama is nearing a decision on whether to commit large numbers of additional troops to the war next year. His top military commander in Afghanistan favors an increase of roughly 40,000, officials have told The Associated Press, which would allow the U.S. military to expand its reach in areas of the country’s south and east now under Taliban sway.

Obama’s visit to the naval air station came after he convened another in a series of White House war council sessions with about a half-dozen Cabinet officials and other top advisers earlier Monday amid Republican criticism that he is taking too long to choose his next move.

The Situation Room session focused on the cooperation between U.S. military and civilian efforts in Afghanistan, White House officials said. Another session may be held later this week.

Obama did not tip his hand on how he might decide. White House press secretary Robert Gibbs told reporters that a decision was still expected in the coming weeks.

A war plan that asks Obama to commit tens of thousands of additional U.S. forces to Afghanistan is too ambitious, a top Senate Democrat said in Washington on Monday.

Sen. John Kerry, the Senate Foreign Relations Committee chairman who was the White House’s point man during last week’s tense talks with Afghan President Hamid Karzai, praised commanding Gen. Stanley McChrystal but said his plan for adding troops in Afghanistan “goes too far, too fast.”

Kerry’s stance would aim for a modest increase in American forces, treading middle ground between Republicans who have said Obama would put soldiers and the country at risk by rejecting McChrystal’s larger request and anti-war Democrats who question whether the United States already has taken on too much in Afghanistan.