BISSAU, Guinea-Bissau — When the army ousted the president here just months before his term was to expire, a thirst for power by the officer corps did not fully explain the offensive. But a sizable increase in drug trafficking in this troubled country since the military took over has raised suspicions that the president’s sudden removal was what amounted to a cocaine coup.

The military brass here has long been associated with drug trafficking, but the coup last spring means soldiers now control the drug racket and the country itself, turning Guinea-Bissau in the eyes of some international counternarcotics experts into a nation where illegal drugs are sanctioned at the top.

“They are probably the worst narco-state that’s out there on the continent,” said a senior Drug Enforcement Administration official in Washington, who spoke on the condition of anonymity so as not to jeopardize his work in the region. “They are a major problem.”

Since the April 12 coup, more small twin-engine planes than ever are making the 1,600-mile Atlantic crossing from Latin America to the edge of Africa’s western bulge, landing in Guinea-Bissau’s fields, uninhabited islands and remote estuaries. There they unload their cargos of cocaine for transshipment north, experts say.