Officials in Mauritania are looking for four suspects they believe are behind the country's largest drug seizure to date.  Police found more than 800 kilograms of cocaine in a van earlier this week in Mauritania's capital, Nouakchott.  Drug experts say this seizure, worth more than $50 million, is another example of West Africa's vulnerability to international drug trafficking. Phuong Tran has more from VOA's West Africa Bureau in Dakar.

Mauritania's deputy state prosecutor, Moulay Abdellah, told VOA two Mauritanians, two Senegalese and one Moroccan were arrested on charges of drug trafficking.  He said officials have also issued arrest warrants for four people who fled.

This latest drug seizure came as part of an investigation of a 600-kilogram cocaine seizure last May in the northern Mauritanian town of Nouadhibou.

A total of 13 men were accused in that seizure, including a Mauritanian employee of the international police organization, Interpol.

Antonio Mazzitelli, the West Africa representative for the U.N. Office on Drugs and Crime, says though recent Mauritanian drug seizures are impressive, they are just a small part of the drugs that make it through West Africa.

"Seizures only picture a small part of the drugs that manage to pass through," he explained.  "As far as cocaine is concerned, the average interception rate worldwide is around 50 percent.  As far as West Africa is concerned, this interception rate is much, much lower."

Mazzitelli says poorly guarded borders, corrupt and underpaid officials, and a weak legal system make West Africa attractive for international criminal networks.

Mohamed Abdellahi Taleb Abedi, the director of Mauritania's National Security Service, says drug seizures are common in Mauritania, because its location makes it attractive to traffickers.

He says it borders the Atlantic Ocean, and is between the drug-producing Americas and the drug-buying Europe.

But Mauritania is not the only West African country attractive to traffickers. Drug seizures have recently taken place in Senegal, Guinea-Bissau, Niger Burkina Faso, Ghana and off the coast of Togo.