U.S. authorities are stepping up counter-narcotics operations in West Africa, a key route for Latin American cocaine bound for Europe and allegedly a major source of funds for al-Qaida groups spreading their tentacles across the continent.

Indictments unsealed in April against senior officers in the armed forces of Guinea-Bissau, the former Portuguese colony that's at the center of the narcotics route from South America to North Africa, marked a sharp escalation in the U.S. Drug Enforcement Administration's offensive.

Among them was Rear Adm. Jose Americo Bubo Na Tchuto, former commander of the tiny state's navy and a suspect drug-smuggling kingpin.

He was arrested April 2 by U.S. agents and local police in international waters off the Cape Verde Islands in the Atlantic Ocean 650 miles west of Guinea-Bissau, which Western authorities consider to be the world's only true narco-state.

Bubo Na Tchuto has been a DEA target since 2010, when he and Guinea-Bissau's air force chief of staff, Gen. Ibraima Papa Camara, were identified by the U.S. Treasury Department as narcotics kingpins in the notoriously unstable country.

They were accused of working with the Latin American cartels moving large shipments of cocaine bound for Europe through West Africa.

Bubo Na Tchuto and others await trial in New York. Trafficking prosecutions are possible in U.S. courts even if illegal narcotics never enter the United States as long as intent to import drugs is proven.

Bubo Na Tchuto was accused of leading a coup attempt in December 2011 in Guinea Bissau, a ramshackle country of 1.5 million people that's sandwiched between Senegal and Guinea on Africa's westernmost point.

The country's latest military-backed coup was staged April 12, 2012, and U.N. officials who monitor the vast narcotics trade in the region say drug trafficking in Guinea-Bissau has grown under the new junta.

The drugs are mostly carried in aircraft, usually cargoes of around 1.5 tons, on 1,600-mile flights across the Atlantic to Africa's western shoulder, landing on remote airstrips dotted around Guinea-Bissau.

A senior DEA official recently commented "people at the highest levels of the military are involved. ...

"In other African countries government officials are part of the problem. In Guinea-Bissau, it's the government itself that's the problem."

The Latin American cartels opened up the transatlantic route several years ago to counter mounting DEA seizures on more direct land and air routes from Central America and Mexico.

The DEA operations have raised the stakes against the drug smugglers and the Islamist militants further north in the Sahara region who provide the routes and protection for the narcotics that eventually are shipped across the Mediterranean to France, Spain and Italy.

The DEA's push consists largely of undercover sting operations, often with agents posing as members of the Revolutionary Armed Forces of Colombia -- as in the capture of Bubo Na Tchuto -- or as Lebanese paramilitaries.

There have been at least six major West African sting operations since December 2009, U.S. officials said.

This is taking place as the United States and France, a former colonial power in North Africa, are intensifying special operations against jihadist groups led by al-Qaida in the Islamic Maghreb.

Pressure on AQIM, and its allies, such as the Those Who Sign in Blood Brigade and the increasingly bloodthirsty Boko Haram group in Nigeria, has been intensified through U.S. bounties of $3 million to $7 million on these groups' leaders.

The U.N. Office on Drugs and Crime says Nigerian crime organizations have increasingly muscled in on the cocaine trade, in some cases edging out the Latin American cartels.

The U.N. agency estimates that 10 percent of the cocaine going to Europe, around 18 tons a year, passes through West Africa, from where it's moved north to the Mediterranean for shipment.

That's up from an estimated 7 percent in 2009 but down from an estimated 27 percent in 2007. This is probably accounted for by the Nigerians taking over the smuggling routes starting in 2008.

The trade is conservatively valued at some $2 billion a year and is considered responsible in part for destabilizing much of the region, including expansion of al-Qaida's operations in North Africa and fighting in Mali where jihadists took over the entire north of the country in early 2012, triggering a French-led military intervention.