Philippe, a former police officer who led the 2004 ouster of President Jean-Bertrand Aristide and later won a senatorial race in the rural Grand'Anse region, is currently in a police facility near the capital's main airport, a police source told Reuters.

It was not immediately clear whether Philippe will continue to be detained.

Local outlet Haiti9 News published footage showing a handful pro-Philippe protesters outside the airport.

Philippe was arrested and handed over to the U.S. Drug Enforcement Administration shortly before swearing in as senator in 2017. A Miami judge sentenced him to nine years in prison, but he was released early in September.

Philippe initially pleaded not guilty, saying he was "kidnapped" by the United States for his political beliefs. He later changed his plea in a deal that prevented him from facing a longer U.S. sentence.

In a statement late last year arguing for his early release, Philippe said he was "looking forward to returning to Haiti and participate in the betterment of his community" in Pestel, on the country's southern peninsula.

Four years after Philippe's arrest, President Jovenel Moise was killed in his home, creating a political vacuum that allowed the rise of extremely violent armed gangs, which now control large parts of the country fueling a dire humanitarian crisis.

Haiti's government - which has lacked elected officials since the last senators' terms expired in January - has been largely absent and Prime Minister Ariel Henry has pledged to hold long-awaited elections once security is re-established.

The United Nations has urgently called on countries to volunteer troops to a U.N.-ratified force to support Haiti's outgunned police, highlighting the importance of progress toward carrying out free and fair elections.