The U.S. is better at rescuing American hostages and communicating with their families than it was when the Islamic State murdered Arizonan Kayla Mueller, a White House spokesman said Friday.

The Obama administration has instituted "important reforms" since then "that have resulted in more effective use of [U.S.] resources, and more effective use of the expertise within the federal government, to sharpen our efforts to secure the return or to rescue American citizens held against their will around the world," White House spokesman Josh Earnest.

He was responding to an allegation leveled by Mueller's father that President Obama did not do enough to rescue his daughter.

"This is a father who is grieving over the loss of his daughter," Earnest said. "I think the grief and sadness that he feels about the fact that his daughter was not successfully rescued — I think is an entirely human response, and one that's entirely understandable.

"There also has been a concerted effort made to improve the way in which the federal government of the United States communicates with families who are in this unspeakable situation, like the Mueller family was," he added.