President Obama received two briefings on the diagnosis of a second Ebola case in Dallas, according to White House officials, and Sen. John McCain (R-Ariz.) urged the president to appoint a "czar" to coordinate the administration's response to the disease.

Obama was briefed Sunday morning by Lisa Monaco, who serves as assistant to the president for homeland security and counterterrorism and is overseeing the interagency response to the disease. Later, according to White House officials, Obama also discussed the situation with Health and Human Services Secretary Sylvia Burwell.

During those conversations, officials said, Obama ordered that the Centers for Disease Control and Prevention conduct its probe of the apparent breach of infection-control protocols in the second Dallas case “as expeditiously as possible" and share the lessons it learns from the incident “quickly and broadly.” He also directed federal officials to “take immediate additional steps” to ensure hospitals and health-care providers across the country are prepared to follow protocols if they need to treat an Ebola patient.

Sen. John McCain (R-Ariz.), who has previously criticized the White House for the number of "czars" it has appointed to coordinate its policy initiatives, said Sunday on CNN’s “State of the Union” that the time had come to establish an Ebola czar. In addition to Monaco, the State Department has appointed former U.S. ambassador to India Nancy Powell to coordinate the diplomatic response to the outbreak.

"From spending time here in Arizona, my constituents are not comforted,” McCain said. “There has to be more reassurance given to them. I would say that we don't know exactly who's in charge. There has to be some kind of czar.”

"I don't think we're comforted by the fact that we were told there would never be a case of Ebola in the United States," McCain added. "Obviously that's not correct."