Kenyan police officer stands guard as 1.1 tonnes of cocaine goes up in smoke at an incinerator in Nairobi (File Photo - 31 Mar 2006)

Commander Daouda Diop, a spokesman for Senegal's national police, says two men from Guinea Bissau, who were traveling to Portugal, were caught and arrested in Senegal with 11 kilograms of cocaine hidden in their luggage.

The commander says Senegal must improve its surveillance in order to react more quickly. Diop says it is hard to catch traffickers because they often belong to a network that helps them escape.

Antonio Mazzitelli with the U.N. Office on Drugs and Crime says traffickers are learning how to outsmart growing surveillance in West Africa, which is increasingly being used as a transit point for drugs moving from Latin America to Europe.

Mazzitelli says one way drugs get into Africa is through what are called mules, smugglers who swallow drug capsules in order to sneak past airport authorities.

"On one plane, there may be thirty to forty human mules. Out of this 30, 40, law enforcement authorities may be able to pick up one, maybe, two," he said. "The other 28 pass through. They do it [on] purpose. They put two knowing that those two will be the most likely to attract the attention of law enforcement officers."

Mazzitelli says Saturday's seizure in Senegal shows that smugglers are attracted to West Africa because of the poor airport security.

"Human mules are starting to not only ingest drugs, but many are moving much bigger quantities within their luggage," added Mazzitelli. "So if on the plane there are three [who] have ingested 900 grams each, there are maybe another four or five [who] have hidden in their suitcases five, seven, ten kilograms."

In June, Senegalese authorities found more than two tons of cocaine stockpiled in two houses outside the capital, Dakar. The seizures were Senegal's largest thus far, and are among the largest in West Africa.

Other recent seizures in West Africa include more than 800 kilograms of cocaine in a van in Mauritania earlier this month, and more than 300 kilos in Benin. Both were the largest seizures in those countries to date.

According to U.N. drug officials, cocaine seizures in West Africa increased seven times between 2005 and 2006, from two tons to 14 tons.