All 50 US states and the District of Columbia (DC) are on alert for possible violent protests this weekend, ahead of President-elect Joe Biden's inauguration on Wednesday.

National Guard troops have been sent en masse to Washington DC, to deter any repeat of last week's deadly riots.

The FBI has warned of possible armed marches by pro-Trump supporters at all 50 state capitols.

Many streets - some miles from the Capitol, the site of deadly rioting on 6 January - have been blocked off with concrete barriers and metal fences.

The National Mall, which is usually thronged with thousands of people for inaugurations, has been shut at the request of the Secret Service - the agency charged with protecting the president.

The Biden team had already asked Americans to avoid travelling to the nation's capital for the inauguration because of the Covid-19 pandemic. Local officials said people should watch the event remotely