President Barack Obama said the United States has put "every resource we have available" to help in the search for a missing Malaysia Airlines jetliner.
Obama made the comments to FOX4's Clarice Tinsley during an exclusive White House interview on Wednesday afternoon.
Philip Wood, 50, of Keller, Texas, is among the 239 people on board the missing flight. Malaysia Airlines Flight 370 went missing 11 days ago.
"We want to send out our thoughts and prayers to all of the families that have been affected, but particularly our American families, who I can only imagine what they're going through with all of the uncertainty that's taken place," Obama said.
Investigators are taking a close look at the flight crew on the plane since the transponder stopped signaling its location midflight and apparently turned the aircraft around and kept flying for multiple hours.
"We have tried to be very careful, saying that we do not have conclusive evidence one way or the other in terms of what happened, but it…as we get more information, we try to make sure that when, when the administration speaks, that we know what we're talking about," said Obama. "But this is a tough situation."
Obama added that he and his administration will continue to work with others around the world "to see if we can get to the bottom of this."
The Associated Press contributed to this report.