Thousands of people have marched on the streets of the Haitian capital Port-au-Prince to demand that President Jean-Bertrand Aristide step down.
Protesters are calling for President Aristide's resignation
Despite police protection, scuffles and stone-throwing occurred as Aristide supporters tried to block the rally.
Stones were thrown and police used tear gas to break up the march. At least 10 people were reportedly arrested.
President Aristide faces growing pressure - from both political opposition, and armed rebel uprisings.
Sunday's march was able to start with protection from the police.
A similar demonstration on Thursday was called off after militant supporters of the Haitian leader erected barricades and lit burning tyres to disrupt it.
As demonstrators marched through the capital shouting "Down with Aristide", the president's supporters threw stones at the crowd.
Protesters threw stones back in return - and tried to encourage those watching from the sidelines to join in, shouting: "If you want Aristide to leave, come out of your homes!"
The political opposition denied any link to the rebels, who seized Haiti's fourth-largest city Gonaives several days ago.
"There is no linkage. There is one thing - they want him out, we want him to resign! We want him to resign constitutionally," said opposition leader "Andy" Apaid.
Another opposition member, Gilbert Leger, said: "We're still dealing with... non-violent means but let me tell you we have one goal." He added: "We do support (rebel) efforts."
The ranks of rebel groups - which are now believed to control about 11 towns and cities across the country - have been fortified by the arrival of organised criminals.
Aristide supporters blocked an earlier attempt to protest
There are reports that they could soon come into possession of a helicopter to help in attacks on the government.
Both the political opposition and rebels in Haiti want the president to resign, accusing him of stealing elections in 2000 and of corruption.
The BBC's Claire Marshall says such a twin-pronged opposition is putting growing pressure on the president.
But he has received some international support.
Earlier in the week, US Secretary of State Colin Powell said that though Mr Aristide's time in power had been disappointing, "regime change" was not the way forward.
In talks with Canada and Caribbean countries, Mr Powell discussed sending foreign police to Haiti, whose 5,000-strong police force is outnumbered and outgunned by the insurgents.