President Rene Preval said Friday that Haiti and the United States will continue joint offensives against drug trafficking, which he described as the biggest threat to his impoverished Caribbean country.

Preval's comments were his first public remarks since U.S. Drug Enforcement Administration agents and Haitian authorities launched a forceful crackdown on suspected drug traffickers in two coastal towns earlier this week.

The agents arrested a Haitian businessman allegedly tied to cocaine traffickers but failed to capture their main target, former rebel leader and presidential candidate Guy Philippe, who is believed to be in hiding.

Preval said the operation resulted from meetings he held recently with DEA Administrator Karen Tandy, and said more actions are planned.

"These aren't operations we want to advertise. We're not going to say what the next step is but there will be other steps," Preval told reporters during a joint press conference with visiting Canadian Prime Minister Stephen Harper.

He called drug traffickers "the single biggest destabilizing factor facing weak countries like Haiti," which has only a few thousand poorly paid police and a notoriously corrupt judicial system.

Shortly after dawn Monday, five helicopters, two airplanes and at least a dozen DEA and Haitian agents converged on the southern town of Les Cayes and the northwestern town of Gonaives, both known receiving points for South American cocaine bound for the United States.

The agents raided Philippe's two-story home in Les Cayes but found only his wife, two children and maid. Philippe led the 2004 rebellion that toppled former President Jean-Bertrand Aristide and has denied past accusations of drug trafficking.

A U.S. law enforcement official said authorities were surprised they didn't find Philippe and had already prepared a press release announcing his capture. The official requested anonymity because the operation is ongoing.

Preval said other suspects have already been extradited to the United States.

Preval did not name the extradited suspects, but Haitian media have identified them as Lavaud Francois, a Gonaives-based businessman arrested in the DEA raid; Bernard Piquion, who was arrested in May with several Haitian policemen as they allegedly transported cocaine; and Raynald Saint Pierre, a former lieutenant in Haiti's disbanded armed forces.

The U.S. investigation is led by the U.S. Attorney's Office in Miami and the DEA.