President Obama praised the sacrifice of 31 U.S. troops who died early Saturday morning in helicopter crash in Wardak Province, Afghanistan.
The Taliban has claimed it shot down the aircraft with a rocket-propelled grenade. Seven Afghan soldiers on board the helicopter also died.
Obama said their deaths would be not be in vain.
“We will draw inspiration from their lives, and continue the work of securing our country and standing up for the values that they embodied,” he said.
"I am deeply saddened by the loss of many outstanding Americans in uniform and of their Afghan counterparts earlier today in Afghanistan," Defense Secretary Leon Panetta said in a statement. "Their courage was exemplary, as was their determination to make this a safer world for their countries and for their fellow citizens."
ABC News reported the crash killed as many as 25 Navy Seals, the elite force that specializes in commando raids, such as the one that killed Osama bin Laden earlier this year.
It is the most casualties American forces have suffered in a single day in Afghanistan.
In June of 2005, 16 U.S. special forces troops were killed when enemy forces shot down their helicopter in Kunar province.
The president recognized the deaths of Afghan soldiers, who have often come under criticism for their fighting capability.
“We also mourn the Afghans who died alongside our troops in pursuit of a more peaceful and hopeful future for their country,” Obama said. “At this difficult hour, all Americans are united in support of our men and women in uniform who serve so that we can live in freedom and security.”
Rep. Dennis Kucinich (D-Ohio), one of Congress’s most outspoken critics of the war, called on Obama to take a step further recognizing all the lives lost in combat.
“The loss of our men and women serving oversees is a deeply-felt tragedy,” Kucinich said. “I call upon President Obama to put the flag at half-mast and to declare a national day of mourning and remembrance in honor of those who died today and all who have lost their lives in Iraq and Afghanistan in service of the United States of America.”
Panetta said the tragedy will not deter from the U.S. mission in Afghanistan.
"We will stay the course to complete that mission, for which they and all who have served and lost their lives in Afghanistan have made the ultimate sacrifice," he said. "They and their families are in my thoughts, in my prayers and in my heart."
This story was updated at 11:40 a.m.