Former Democratic and Republican US presidents have spoken out against the violent protests by President Donald Trump's supporters in Washington.<br/> The members of the world's most exclusive club reacted after rioters stormed the US Capitol building to try to prevent legislators from certifying Democratic president-elect Joe Biden's victory. Mr Trump maintains that the election result was rigged, despite officials and courts rejecting his claims, and asked his supporters to rally in the capital for a protest on Wednesday. Former Democratic president Jimmy Carter, who served from 1977 to 1981, said that he and wife Rosalynn were troubled by the violence that ensued. <br/> "This is a national tragedy and is not who we are as a nation," he said in a statement released on Twitter by the Carter Centre. Former president Bill Clinton, a Democrat who held the office from 1993 to 2001, called the violence by pro-Trump protesters "an unprecedented assault on our Capitol, our Constitution, and our country". "The assault was fuelled by more than four years of poison politics spreading deliberate misinformation, sowing distrust in our system, and pitting Americans against one another," Mr Clinton said in a Twitter thread. "I have always believed that America is made up of good, decent people. I still do." Former two-term Republican president George W Bush described the rioting as nauseating and upsetting. "This is how election results are disputed in a banana republic," he wrote in a statement that also categorised the demonstration as an insurrection. "I am appalled by the reckless behaviour of some political leaders since the election and the lack of respect shown today for our institutions, our traditions, and our law enforcement," Mr Bush said. "Insurrection could do grave damage to our nation and reputation. In the United States of America, it is the fundamental responsibility of every patriotic citizen to support the rule of law" Mr Bush tried to calm the sentiments of those who do not accept Mr Biden's victory. "To those who are disappointed in the results of the election, our country is more important than the politics of the moment," he said. Mr Trump's predecessor, former President Barack Obama penned a statement that blamed Mr Trump for creating the climate for such division. "History will rightly remember today's violence at the Capitol, incited by a sitting president who has continued to baselessly lie about the outcome of a lawful election, as a moment of great dishonor and shame for our nation," Obama wrote. He also issued a challenge to Republican elected officials in Washington. "Republican leaders have made a choice made clear in the desecrated chambers of democracy. They can continue down this road and keep stoking the raging fires, or they can choose reality and take the first steps toward extinguishing the flames," he added. Perhaps the most striking statement came from former Democratic vice president Al Gore, who lost to Mr Bush in the controversial 2000 election ultimately decided by the Supreme Court. Despite vote discrepancies and other controversies, Mr Gore peacefully conceded following the Supreme court ruling. "Today, America looked into the abyss created by Donald Trump and my fervent hope is that even his enablers will now finally draw back in horror," he wrote.