International drug officials continue to worry that West Africa's porous borders and weak law enforcement are attracting drug smugglers shipping to Europe. They say they have evidence criminals are looking to Mauritania's largely unguarded coastline, airport, open deserts and facilities to funnel and process top-dollar illegal drugs. Phuong Tran has more from the fishing town, Nouadhibou, Mauritania.

Law enforcement officials from nine countries had been pursuing one of the arrested men, Sidi Mohamed Ould Haidalla. They say he is behind the country's largest known cocaine seizure, in May.

Drug investigators say the shipment of more than 600 kilograms of cocaine was destined for Haidalla, son of a former Mauritanian president.

Mohamed Yahya is governor of Nouadhibou, where security officials tracked down the abandoned $20 million worth of cocaine at the airport.

The governor says he has doubled the number of guard posts around the city and also the number of undercover agents. But Yahya says he needs more money.

He has asked for more funds from the national government to pay informants to report possible drug activity and to buy 4x4 patrol vehicles.

Security forces survey the hundreds-of-kilometers-long coast mostly by foot and camel.

United Nations Office of Drugs and Crime West Africa Representative Antonio Mazzitelli says, although seizures have been happening for years in West Africa, there is now also evidence of drug processing.

"A chemical precursor [finishing product] here might be much more easily available than in Latin American countries, where there are quite well developed systems of control," he said.

He says processing cocoa into cocaine in West Africa generally cuts down the price for sellers, because of cheaper chemical products.

Mauritania National Security Service Director Mohamed Abdellahi Taleb Abedi says his forces have found evidence of drug processing and have detained a number of people in the capital, Nouakchott.

He says investigators have not yet found the final drug product, only a chemical form of the drug before it is processed.

He says some of the suspects will be released, but others will be held longer for the investigation.

Abedi dismisses lawyers' allegations evidence for this drug case is being gathered through the use of torture.

U.N. drug representative Mazzitelli says smuggling investigations in West Africa are still a fragile and sometimes corrupt enterprise.

"We are really scared in certain countries drug money are becoming, to a certain extent, widely available in the corridors of power," he said. "Because the very moment the drug money starts to infiltrate power, then it will be extremely difficult for everybody to get rid of it."

But newly-elected Mauritanian President Sidi Mohamed Ould Cheikh Abdallahi says his government is committed to transparent, legal drug investigations, as well as the pursuit of all criminal drug activities.

Spanish officials recently reported finding 800 kilograms of cocaine, dropped in the sea shortly before an emergency plane landing in the Canary Islands, last month.

Based on information they have received, U.N. drug officials say the small plane most likely left from northern Mauritania or Western Sahara.