Barack Obama asked his Homeland Security Secretary Jeh Johnson to skip today's inaugural ceremony, in case of an attack on the Capitol or some other accident.

Johnson was the 'designated survivor, the cabinet member taken to a secure location in case something happens to the president, vice president, congressional leaders and other secretaries ahead of him in the line of succession, the Obama White House said.

But a Republican senator has since said that he was the designated survivor. President Pro Tempore of the Senate Orrin Hatch says Donald Trump asked him.

Barack Obama's Homeland Security Secretary Jeh Johnson was asked to skip today's inaugural ceremony, in case of an attack on the Capitol or some other accident. But President Pro Tempore of the Senate Orrin Hatch says Donald Trump asked him

The 'designated survivor' is usually a cabinet member, taken to a secure location in case something happens to the president, vice president, congressional leaders and other secretaries ahead of him in the line of succession

The president names a designated survivor anytime the cabinet and Members of Congress in the line of succession convene, as they did today at the U.S. Capitol

Hatch's office said in a statement that he was 'absent from the ceremony in keeping with procedures for the continuity of government' and was at an 'undisclosed location for the duration of the event.'

'At the request of President Donald Trump, I am honored to fulfill the role of designated presidential successor during the inauguration,' he said in a statement.

'As much as I would have liked to participate in the ceremony and festivities, I am honored to perform this important constitutional duty, which ensures the continuity of government.'

Because President Donald Trump's cabinet hasn't been confirmed, it seems Obama asked one of his cabinet secretaries to do the job today, even though Hatch, a Utah senator, outranks him.

The Obama White House said that Johnson was tapped to be the designated survivor to ensure the continuity of government.

Any person in the line of succession can be the designated survivor, including members of Congress, as long as they were born in the United States. Typically the role is filled by someone in the president's cabinet however.

Johnson and Hatch shared the designated survivor designation during Obama's 2016 State of the Union. The White House said it asked Johnson, but Hatch said he was skipping the speech, too.

For Johnson to become president, President Trump, Vice President Mike Pence and every other member of Obama's cabinet would have had to be indisposed.

The Homeland Security secretary is the last in the line of succession.

After Trump and Pence, the power is handed to House Speaker Paul Ryan, then President pro tempore of the Senate, Hatch. Both are Republicans.

Next in line is the secretary of state, John Kerry, then Treasury, Jacob Lew, Defense, Ash Carter and attorney general, Loretta Lynch.

Interior is currently skipped over. Secretary Sally Jewell is not a natural-born American, a requirement to serve as president.

The president names a designated survivor any time the cabinet and Members of Congress in the line of succession convene, as they do each year for the president's State of the Union address, also at the U.S. Capitol.

Johnson filled the role today at the request of the exiting president, Obama, as top current and former government officials gathered at the West Front of the Capitol in Washington, D.C. for Trump's inauguration. Hatch sat it out, too, at the request of the incoming president, Trump, he said.