An "army" of protesters have marched on Capital Hill in Washington DC today as Facebook CEO Mark Zuckerberg prepares to testify at Congress.

A US Capitol Police officer has been shot at the Capitol Visitor Centre complex, and a suspect was taken into custody, Capitol officials and police said.

Barack Obama has used his biggest speech of the year to push for narrowing the gap between rich and poor – and pledged to sidestep Congress “whenever and wherever” necessary to bypass the political gridlock that has bedevilled his presidency.