By Arul Louis New York, Jan 19 : The Capitol area of Washington hunkering down under a pall of fear was put in a lockdown on Monday when a fire broke out in a camp of homeless people near the site of Wednesday's inauguration of Joe Biden as president and Kamala Harris as vice president. A rehearsal for the inauguration -- the swearing-in ceremony -- was disrupted when the fire and explosions happened, but it was not found to be a security threat as only propane tanks at the camp exploded from the accidental fire. Neither Biden nor Harris was at the rehearsal. The military band and others participating in the rehearsal were ordered to take shelter in a secure area. The lockdown was lifted after the fire was not considered a threat by officials. The heart of the city looks like an armed camp with about 15,000 National Guard troops deployed in response to the storming of the Capitol by some of President Donald Trump's supporters on January 6 and the breakdown of security. About 10,000 more are expected. The Federal Bureau of Investigation (FBI) has warned of threats from extremists to Washington and state capitals around the country before and during the inauguration. The presence of some police and other security personnel as well as several ex-service personnel at the attack on Congress has raised fears that the troops deployed for inaugural security may themselves be a security threat. The FBI and other agencies have been vetting the National Guard at the request of the Defence Department. National Guard Commanding General William Walker told Fox News TV the vetting was a matter of "abundance of caution" being carried out "to make sure that we have the right people in the security bubble". None of the attacks, riots or large protests that had been anticipated during the weekend or on Monday, the public holiday celebrating the birthday of civil rights leader Martin Luther King, have materialised. But the fears of attacks or disruptions for the inauguration persist. The January 6 riots took place after Trump addressed a rally urging his supporters to protest the election of Biden, which he said was the result of massive fraud. About 50 legal challenged by him and his supporters to the election have been thrown out by courts. Many of his supporters marched to the Capitol, which houses Congress. just as the Senate and the House of Representatives were in the process of ratifying the votes of the electoral college electing Biden. A section of the rioters overwhelmed security and rushed inside the Capitol building, entering the Senate chamber and the office of Speaker Nancy Pelosi, while members of Congress were evacuated to safety. Five people, including a police officer, died during the riot and a nation-wide hunt is on for those who entered the Capitol and several have already been arrested.. The House impeached Trump on Wednesday, charging him with inciting an insurrection and threatening democracy. Under the impeachment process, the Senate is to hold a judicial-style trial of Trump with the senators acting as jurors. (Arul Louis can be reached at arul.l@ians.in and followed on Twitter at @arulouis) /IANS