Thousands of anti-government protesters have clashed with police in Haiti's capital Port-au-Prince.
They burned tyres and threw stones at officers who responded with tear gas.
The protesters want President Michel Martelly and Prime Minister Laurent Lamothe to resign and long-overdue elections to be held.
Some protesters accused the US of supporting Haiti's leadership and called on Russian President Vladimir Putin for help.
Hundreds succeeded in reaching the National Palace, an area which has been restricted for several years.
One protester, who gave his name as Reginald, said: "Today is a victory against President Martelly who destroys the country, for two years we (are not allowed) to cross in front of the National Palace."
President Martelly was supposed to call elections in 2011 but they have been postponed in a stalemate between the government and a group of opposition senators over electoral law.
Haiti is also still struggling to recover from a 2010 earthquake.
Opposition politicians accuse President Martelly of wanting to rule by decree.
The government argues that opposition politicians are also dragging their feet in the hope of extending their time in office without elections.