Washington locked down as Joe Biden prepares to take oath of office

More than 25,000 troops and police have been called to duty.

National Guards deploy ahead of President-elect Joe Biden’s inauguration ceremony (Matt Slocum/AP)

The inauguration of President-elect Joe Biden will take place in a Washington on edge, after the deadly riot at the US Capitol unleashed a wave of fear and unmatched security concerns.

And law enforcement officials are contending not only with the potential for outside threats but also with rising concerns about an insider attack by troops with a duty to protect him.