Philippe, 48, was participating in a live radio talk show in a Port-au-Prince suburb when heavily armed antinarcotics police took position outside the studio.
Philippe, 48, was participating in a live radio talk show in a Port-au-Prince suburb when heavily armed antinarcotics police took position outside the studio, shooting into the air and sparking a panic in the neighborhood, according to journalists at the scene.
Philippe emerged from the building in handcuffs and was loaded into a police vehicle.
A national police spokesman confirmed the arrest but declined to tell reporters the charges faced by Philippe, who has close ties to the country's president-elect Jovenel Moise.
A local radio station reported that Philippe -- who does not yet enjoy immunity from prosecution as a senator because he has yet to take the oath of office -- was the subject of a US extradition request and was being taken to the airport.
A lawmaker who asked not to be named told AFP Philippe was indeed at the airport, without offering further details.
Philippe, who was elected to represent the Grande Anse department in southwestern Haiti, helped lead an armed rebellion against then-president Jean-Bertrand Aristide in 2004 that led to Aristide fleeing the country.
The US Drug Enforcement Administration (DEA) has long sought Philippe on drug trafficking charges. The DEA was not immediately available for comment on the case.
But those charges did not stop Philippe from living in the open in his political fiefdom of Pestel, located 150 kilometers (93 miles) from Port-au-Prince.
Haitian police concluded in July that Philippe was the mastermind of an attack against a police station in Les Cayes in May, which left one officer dead and two others seriously wounded.
Philippe has consistently denied those claims, and Moise, whose election to the presidency was confirmed this week, appeared at the new senator's side at a campaign event in Pestel.
Some lawmakers criticized Philippe's arrest as illegal, but until he takes the oath of office scheduled for Monday, he does not enjoy immunity.
In a statement Thursday, the US embassy in Port-au-Prince asked employees to stay home due to an "ongoing law enforcement / security situation" and urged all US nationals to shelter in place.
Supporters of Philippe blocked roads in Pestel with tree trunks and blazing tires.