National Guard members walk toward the US Capitol in Washington, the United States, on Friday. JOSHUA ROBERTS/REUTERS Tensions were high across the United States on Sunday amid threats by protesters to descend on statehouses throughout the nation, as law enforcement officials girded for possible violence ahead of President-elect Joe Biden's inauguration in Washington on Wednesday. More than a dozen states activated National Guard troops to help secure their capitol buildings following an FBI warning of armed protests, with right-wing extremists emboldened by the deadly attack on the US Capitol in Washington on Jan 6. There were scattered demonstrations on Saturday, but statehouses remained mostly quiet. Security officials eyed Sunday as the first major flashpoint as that was when the anti-government "boogaloo" movement made plans weeks ago to hold rallies in all 50 states. The FBI warned police agencies of possible armed demonstrations outside all 50 state capitol buildings through the inauguration on Wednesday, fueled by President Donald Trump's supporters who believe his claims of electoral fraud, Reuters reported. In the US capital and at state capitals across the country, law enforcement authorities backed by National Guard troops braced for possible violent protests. Major General William Walker, the commanding general of the District of Columbia National Guard, said on Saturday that about 10,000 guardsmen were in the district and up to 25,000 were expected by Tuesday night, the eve of the inauguration. On Saturday, more troops arrived in Washington by planes, in rented buses and in military trucks, The Associated Press reported. The guardsmen are being billeted in some 70 hotels across the region, some outside the district itself, Walker said. Alongside the unprecedented show of force, security measures by shops and restaurants have been ramped up in the US capital. Windows and doors on some buildings along Connecticut Avenue in northwestern Washington, DC, have been boarded up, a seemingly higher level of precautions than were in place during the sometimes violent anti-racism protests in the summer. In addition, the states of Michigan, Virginia, Wisconsin, Pennsylvania and Washington have activated their National Guards to strengthen security. In Michigan, where armed protesters entered the capitol in Lansing in April, a commission that manages the building and its grounds has voted to ban the open carrying of guns in the building. "We are prepared for the worst, but we remain hopeful that those who choose to demonstrate at our Capitol do so peacefully," Colonel Joseph Gasper, Michigan State Police director, said at a security briefing on Friday. On Wednesday, Inauguration Day, Biden will sign orders for the US to rejoin the Paris climate accord, reverse Trump's ban on people from certain Muslim majority countries from entering the US, and address the raging coronavirus pandemic by issuing a mask mandate, according to a memo circulated by Ron Klain, Biden's incoming White House chief of staff. "President-elect Biden will take action－not just to reverse the gravest damages of the Trump administration－but also to start moving our country forward," Klain said, as police staged a nationwide security operation ahead of the inauguration. An inauguration rehearsal scheduled for Sunday was postponed to Monday because of security concerns, Politico reported. Biden's team also canceled the president-elect's plan to travel on Monday by Amtrak train from Wilmington, his hometown, to Washington, DC, because of heightened security concerns, according to US media reports. At noon on Wednesday, Biden and Vice-President-elect Kamala Harris will be sworn in on the steps of the Capitol. Three former US presidents－Bill Clinton, George W. Bush and Barack Obama and their spouses－Vice-President Mike Pence, Supreme Court justices and members of Congress will be seated there. Trump has said he will skip the inauguration. Soul-searching The protest and rioting in Washington on Jan 6, which left five dead after supporters of Trump stormed the US Capitol, has prompted soul-searching. Nearly three-fourths of voters said democracy is in trouble in the country, according to a Quinnipiac University national poll of registered voters released last week. "I'm a little surprised at that number, because you would actually think it would be 100 percent. Like everybody should recognize democracy is in trouble when people are storming the Capitol building," Darrell West, director of governance studies at The Brookings Institution, said in a podcast on Friday. As of Friday, the National Park Service had issued only two permits that together allow for 75 people to demonstrate around the inauguration, according to Mike Litterst, a spokesman for the federal agency. The Park Service was also processing five permit applications, including two requests for events at which 5,000 people were expected, he said. Workers used cranes to place concrete barriers throughout Washington, where National Guardsmen with rifles strapped to their torsos were stationed at intervals. The National Mall and other iconic district landmarks were also blocked off, and bridges into the city were to be closed, along with dozens of roads. Officials said threats to the district range from armed insurgents to possible attempts to plant explosive devices at so-called soft targets. In downtown Washington, officers arrested a Virginia man who presented an "unauthorized inauguration credential" at a Capitol Police checkpoint on Friday evening. He was found to have a loaded handgun and more than 500 rounds of ammunition, according to court papers. Responding to news of the arrest, Democratic Representative Don Beyer of Virginia said the danger was real and the city was on edge. "Anyone who can avoid the area around the Capitol and Mall this week should do so," Beyer wrote on social media. Appeals for Guard troops Military leaders recently appealed to state governors for more National Guard troops for Washington. The governors, who have authority over their National Guard, sent anywhere from a few dozen to 1,000 each. Others declined to in order to protect their own state capitals. Appeals for more Guard troops underscore the Pentagon's limits on the use of active-duty troops. Under the law, they can't be used for law enforcement, and officials are determined to avoid the appearance of armed active-duty forces being used against US citizens on American soil. Many of the National Guard troops will be armed. Oregon agreed to send 30 troops to Washington, but Governor Kate Brown said she turned down the federal request to send at least 100 more. Connecticut initially agreed to send 100 Guard troops and on Friday agreed to send 200 more. "The peaceful transfer of power is a central tenet of American democracy, and Connecticut stands ready to aid in the protection of our country," said Connecticut Governor Ned Lamont. Agencies contributed to this story.