National Guard deployed to Washington, DC, to provide security for President Joe Biden's inauguration have tested positive for the coronavirus, a US official told news agency Reuters on Friday.The US government imposed unprecedented security measures in the city following the deadly 6 January attack on the Capitol by supporters of former President Donald Trump, including fences topped with razor wire and checkpoints manned by the National Guard.Thousands of national guard troops from across the country arrived in Washington in response to escalating security threats and fears of further rioting.Guard forces were scattered around the city this week, helping to secure the Capitol, as well as monuments, Metro entrances and the perimeter of.