Police have arrested Haiti's Senate president and two other politicians, all of them supporters of former president Jean-Bertrand Aristide.
The three pro-Aristide politicians deny involvement in any crime
The arrests are linked to the killing and beheading of three police officers.
Violent clashes involving supporters of the ousted president have taken place in Haiti's capital Port-au-Prince over the past three days.
Mr Aristide, who was flown out of the island following a revolt in February, claims he was kidnapped by US agents.
The arrests ended an 11-hour standoff in which dozens of police officers surrounded the building of an independent radio station, Radio Caribes FM.
The politicians had just taken part in a show in which they exchanged views with Aristide opponents, allegedly to call for a peaceful solution to the outbreak of violence.
Senate President Yvon Fuille said his arrest was illegal because it violated his immunity.
"They are kidnapping me. They have no reason to arrest me, it is an illegal arrest," Mr Fuille said while he was led away from the building.
The headless bodies of three police officers were found on Friday, sparking fears that Mr Aristide's most violent supporters might be imitating Iraqi kidnappers.
They policemen are believed to have been killed during violent rallies in support of Mr Aristide's return from his exile in South Africa.
"Aristide's partisans have begun an urban guerrilla operation they call Operation Baghdad," said human rights activist Jean-Claude Bajeux.
"The decapitations are imitative of those in Iraq, and they are meant to show the failure of US policy in Haiti."
But pro-Aristide officials put the blame on the US-backed interim government.
They are calling for an end of the "occupation" after a multinational military force led by the USA was sent to the island in the aftermath of Mr Aristide's ouster to restore law and order.
UN peacekeepers took over in June, but the 3,000-strong mission is struggling to keep control.
Several hundred have been sent to the north of the country to the flood-stricken port city of Gonaives, where the storm took its highest toll, killing more than 1,500 people.
In a separate development, the Brazilian general in charge of the UN peacekeeping force, Augusto Ribeiro Pereira, has called for more troops and emergency aid.
He said his troops were working seven days a week, 24 hours a day and were exhausted.
His remarks came as Brazil sent 15 metric tons of food and medical supplies to help the country recover from the devastation caused by Hurricane Jeanne last month.