"Frustrating" search for family of U.S. couple missing in Brussels

At least a dozen Americans were hurt in the Brussels attack. The State Department said it does not know of any Americans killed in the terror strike, but at least two are considered missing, reports CBS News correspondent Vladimir Duthiers.

Sheila Shell is headed to Belgium to track down her son, Justin Shults. She said the Tennessee native - and his wife Stephanie, who is from Kentucky - were inside the airport during the attack.

"Justin has been wanting me to come to Brussels and see him but this is not the way that I wanted to go see him," Shell said. "One minute, they were there and then they weren't and we've been searching and looking for them ever since."

Shell said the State Department called her Wednesday, saying the couple was "on a list of people provided by the Belgian government," but their status was unclear.

"It was very frustrating trying to get somebody and finally I called Senator Bob Corker's office and voila, then things started happening," said Shiela's husband, John Shell.

Corker's office reached out to Belgian officials, but no one could confirm the couple had been found.

New York residents Sascha and Alex Penczowski are also among the missing.

Karen Northshield works as a personal trainer in Brussels and was reportedly on her way to the U.S. to visit family. She is in intensive care but expected to live.

Three Mormon missionaries from Utah survived the terror strike. Among them is 19-year-old Mason Wells, who was treated for burns and shrapnel injuries. His parents are traveling to Brussels to see him.

"The first step is him, his care, his well-being, is he okay? What's his medical care? And then how do we get him home?" said his father, Chad Wells.

"We know Mason will want to get back to a regular life and not want to sit and dwell on this," said his mother, Kymberly Wells.

Jeff Slaughter was on his way home to Louisiana when the bombs went off.

"Ceiling tiles began raining down all over. And so all I could think about at that point was just, get out," Slaughter said.

He ran out of the airport to a triage area but was unhurt.

"I think everyone was in shock," Slaughter said.

NBA Hall of Famer Dikembe Mutombo was inside the airport too, a few hundred feet from the first blast. He arrived in Atlanta Wednesday.

"I want to go and kiss my wife and the kids and give them a big hug," Mutombo said.

One hundred fifty people remain in hospitals across Brussels, at least 61 of whom are in intensive care. Many have severe burns and shrapnel in their bodies, similar to what we saw after the Boston bombings.